Transcript +2 - The Institute of Chemistry - The Hebrew University of Jerusalem
Slide 1
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 2
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 3
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 4
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 5
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 6
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 7
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 8
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 9
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 10
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 11
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 12
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 13
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 14
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 15
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 16
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 17
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 18
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 19
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 20
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 21
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 22
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 23
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 24
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 25
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 26
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 27
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 28
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 29
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 30
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 31
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 32
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 33
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 34
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 35
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 36
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 37
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 38
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 39
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 40
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 41
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 2
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 3
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 4
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 5
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 6
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 7
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 8
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 9
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 10
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 11
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 12
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 13
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 14
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 15
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 16
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 17
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 18
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 19
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 20
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 21
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 22
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 23
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 24
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 25
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 26
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 27
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 28
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 29
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 30
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 31
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 32
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 33
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 34
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 35
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 36
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 37
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 38
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 39
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 40
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials
Slide 41
Nanoporosity – where is it useful in chemistry?
David Avnir
Institute of Chemistry
The Hebrew University of Jerusalem
Nano Center Meeting, Ashkelon, March 29-30, 2015
1. The material at focus - silica
Silica
Controlled nanoporosity
Surface area and
pore volume of
silica as a
function of pH
and water/silane
ratio in the solgel process
Functionality within a sol-gel matrix
Monoliths
Powders
Particles
This-films
2. Chemical sponges – diffusion considerations
VTS: An efficient bromine sponge
Sol-Gel Sponges
O
O
Si
O
Si
O
O
O
HO
Si
O H
O
O Si C
O
Si
O Si
O
Si
O
OH
Si
H
O
H 2C
OH
Si
O
Si
O
O
OH
Si
O
Si
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H
CH
O
O
HO
H
2
O
Si
C
H
O
O
H
OH
H 2C
OH
O
OH
H 2C
H
2
Si
HO
H
O
silica cage
O
O
H
CH
O
Si
C
H 2C
-
CH
CH
H
OH
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
Br 2 /H
O2 O
Br 22 /H
Si
HO
hydrobromic
OH
O
OH
OH
acid
Br
CH
OH
-
H
O
2
H
Br
Br
O
H
H
O
Si
O
HO
Br
H
-
CH
H 2C
Br
O H
O
C OH
O Si
O
CH 2
Si
Br
vinyl group
Hagit Frenkel-Mullerad
O
OH
O Si CH
O
CH
Si
HO
Si
O
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
2
HO
Br
O
OH
CH 2
CH
Si
OH OH
Si O
OH OH
OH
Si
HC
O
O
HO
Si
Si
O Si O
O
Si
Si
O
O
O
Si
O
O
O
O
O
OH
O
H
Si(CH 2 )n
C
C
H
H
Br 2
HO
H
Si(CH 2 )n
2H 2 O
H
C
C
H
H 3O
Br
The reaction kinetics can be followed in two ways:
1.
Following the visible absorption of bromine
2. Following the decrease in pH
Br
Kinetics of the reaction through
follow-up of Br2 consumption
Vinylated silica
Kinetics of the reaction as detected by HBr release
2.4
pH
2.35
X10
slower
2.3
2.25
2.2
0
10
20
30
40
50
Time (min)
Kinetics of reactivity in nanopores depends on the
analytical probe!
Kinetics depends also on the fine details of the hybrid material,
even if the functionality is the same:
Vinyl, allyl, butyl, octyl.
The shorter chains are much more reactive than the longer ones why?
Time (s)
1.1
1
A/Ao
0.9
0.8
0.7
VTS
ATS
BTS
OTS
0.6
Initial rates
0.5
0
2
4
6
Time (s)
8
10
12
A schematic view of the possible micellar nano-phase zones
O
O
Si
O
O
O
Si
O
Si
O
O
Si
O
O
O
Si
O
O
O
O
Si
Si
O
Si
O
O
O
O
O
O
O
O
Si
O
O
O
Si
O
Si
O
O
Si
Si
Si
O
O
O
O
O
Reactivity depends on the specific nano
structure of the hybrid material
3. Photochemistry
Example 1: Solar energy storage - solving the problem of back-reaction
Light
Py* - the donor
Py
Electron
transfer
Py* +
MV2+ - the acceptor
2MV.+ + 2H3O+
Useful reaction
Energy storing pair
2MV2+ + H2 + 2H2O
The classical problem:
MV.+ + Py+
MV.+ + Py+
back-reaction
MV2+ + Py
The nanoporosity approach:
I. Separate spatially the donor and the acceptor by entrapment in a sol-gel matrix
II. Allow them to communicate through the nanopores with a shuttler
Py*@silica + TV2+
TV+ + Py+@silica
MV2+@silica + TV+
TV+2 + MV+@silica
Four hours, 5% yield of separated pair
TV2+
N
N
Py
MV2+
2B r
The redox potential of the MV pair is smaller than that of the TV pair
TV+ + Py+@silica
A. Slama-Schwok, M. Ottolenghi
Py@silica + TV2+
Example 2: Affecting the direction of photochromism by tailoring
the surface of the nanopores
Isomerization of spiropyrans
D. Levy
Controlling the directionality of photochromism
Colorless
Colored
Reversed
photochromism in
silica sol-gel matrices
…but normal photochromism in ethylated silica
Colorless
Colored
3. Sensors:
Extraction of a library of reactivities from a single molecule
Getting a library of acid/base sensors from a single molecule
nanopore effects
+
Anionic
AF
Zwitterionic
ET(30)
Claudio Rottman
Affecting the immediate environment by co-entrapment of surfactants
within the nanocages
ET(30), an acid or a base – your choice: The interpretation
Continuous range of acids/bases by using a surfactant mixture at varying proportions
ET(30)
Huge pKi shift for AF: 8 orders of magnitude
4. Catalysis
1st example: Superior synergistic catalyst for green chemistry
Two components in a nano-cage: Catalytic synergism
Hydrogenation of chlorinated environmental pollutants
Chlorophenols
6h
OCH
2
+
CO 2 H
Cl
2,4,5-T
(44%)
H2O
Cl
O
=
OH
OH
24 h
ClCH 2 CH 2 Cl
Cl
(75 % )
(26%)
The combined catalyst:
Pd nanoparticles + [Rh(cod)Cl]2
Cl
PCBs
Cl 3
Cl 3
24 h
hexane
(99%)
H
DDT
Cl
C
Cl
24 h
hexane
CCl3
H
C
(90%)
CH3
Cl
Cl-dioxins
Cl
O
O
Cl
R. Abu-Reziq, J. Blum
24 h
ClCH 2 CH2Cl
O
(93%)
O
Mechanism suggested by Bianchini, Psaro et al:
The confinement of
the two catalysts
within a cage
C. Bianchini, R. Psaro et al, J. Am. Chem. Soc.
2nd example: One-pot multistep catalytic processes
with opposing reagents
A
a c id
B + C
base
D
Cutting the need for separation steps
F. Gelman, J. Blum
Three steps oxidation/reductions in one pot
RhCl[P(C6H5)3]3
F. Gelamn, J. Blum
91%
5. Imprinted nanoporosity
4th example: Tailored nanoporosity by imprinting
Directing the seterochemistry of a reaction
Forcing a cis-product in the Pd-acetate catalyzed Heck reaction
9:1
1:1
D. Tsvelikhovsky, J. Blum
Electrochemical recognition of the imprinting molecule: Dopa
L-Dopa
D-Dopa
HO
CH 2 CHNH
Current / mA
Current (mA)
HO
Silica sol-gel thin
films, 70 nm
2
COOH
HO
HO
HO
OH
HO
CH 2 CH 2 NH
HO
2
CH 2 CO 2 H
D. Mandler, S. Fireman
6. Enzymatic reactions - enhanced stability
Protection from heat
New, very mild entrapment method in alumina:
Al(C3H7O)3, pH 7.3, ultrasound
OVA@alumina
Very large shifts in the denaturing temperatures
V. Vinogradov, 2014/5
Not only thermal stability, but increase in activity up to 60oC
Acid phosphatase@Alumina
… and stability to repeated
cycles of heating to 60oC
and cooling
The activity at 750C, is higher than at
room temperature by about two
orders of magnitude.
# (AcP, 1): Treatment of enzyme deficiency
diseases
Arrhenius analysis
ACP@Alumina
oCoC
60-70
60-70
The pre-factor of the
entrapped enzyme
A = 3.54.1014 sec-1
six orders of
magnitude higher (!)
than that of the free
enzyme
4.34.108 sec-1
k Ae
Ea
RT
7. Merging all of the above
Protection of an enzyme from strong oxidative conditions:
Alkaline phosphatase protected from bromine
VTS: An efficient bromine sponge
O
O
Si
O
O
O
O
O
HO
Si
H
Si
O
O
CH
OH
2
OH
Si
O
H
OH
O
Si
O
O
OH
Si
O
OH
HC
O
Si
Si
O
O
O
Si
C
Si
H
O
HO
OH
Si
O
O
HO
H 2C
O
H 2C
Si
O
Si
HO
H
CH
O
O
H
H
2
O
Si
C
H
O
CH
H 2C
H
Si
HO
H
silica cage
O
O
H
OH
H 2C
OH
O
-
O
Si
C
H 2C
CH
O
O Si C
O
Si
O Si
O
H
OH
Si
O
hydrobromination
O
O
O
Si
O
O
O
Si
Si
O
O
O
vinyl group
Si
HO
O
OH
OH
Si
O
O
OH
-
Br
Br
-
CH
O
HO
Br
H
O
2
H
H
Br
O
O
Si
H 2C
OH
O Si CH
O
CH
CH
OH
O
hydrobromic
O
Si
Br
OH
O H
O
C OH
O Si
O
H
CH 2
Si
Br
Br 2 /H
O2 O
Br 22 /H
HO
Si
O
H
H
O
Si
O
HO
H 2C
Br
C
Si
H
HO
O
O
Si
O
O
Br HO
H 2 C CH Si
Si
O
O
HO
Br
O
CH 2
CH OH
OH
Si
OH
OH OH
OH
Si
HC
HO
Si
Si
Si
O
O
O
Si
Si
O
O
O
Si
O
O
O
O
O
2
acid
H. Frenkel-Mullerad, R. Ben-Knaz, 2014
O
One-pot enzyme/catalyst pair
H 2C
C H (C H 2 ) 8 C O O H
+ CH 3 (CH 2 ) n CH 2 OH
Catal@S-G
H2
Lipase@S-G
A
a c id
B + C
CH 3 (CH 2 ) 9 COOCH
2
(CH 2 ) n CH 3
base
D
C a ta lys ts : R h 2 C o 2 (C O ) 1 2
0.6 mmol acid, 2.5 mmol alcohol
0.01 mmol catalyst, 11U lipase
F. Gelman, J. Blum
R h (P P h 3 ) 3 C l
Conclusion
Better materials based on chemistry
Better chemistry based on materials