Transcript Ohio_2010_H3NAgCl.pptx

1
Microwave Spectra and Structures of
H2O-AgCl and H3N-AgCl
by
Nicholas R. Walker, Victor A. Mikhailov, Felicity J. Roberts,
Stephanie J. Harris, Susanna L. Stephens and Anthony C. Legon
Rod
rotater
Laser
arm
Gas line
attached
to solenoid
valve
H
N
H
Microwave emission
antenna
Ag
Cl
Objectives
• Apply microwave spectroscopy to study interactions of broad
significance in inorganic chemistry. Examples include complexes
formed between CO, H2S, H2O, NH3 and the noble metal atoms Cu
and Ag.
• Establish laser ablation as a general method for the production of
metal-ligand complexes for study by microwave spectroscopy.
• Compare units such as H2S-AgCl, H2O-AgCl with their hydrogenbonded analogues, H2S-HCl, H2O-HCl to identify common trends.
• Previous works include studies of OC-MX by Gerry and co-workers.
Also N2-MX and H2S-MX by Walker, Legon and co-workers.
Balle-Flygare FTMW Spectrometer
Laser arm
Rod rotater
532 nm Nd:YAG laser
Focusing lens
Solenoid valve
Gas line
Adiabatic expansion of
CCl4 / H2O / NH3 / Ar
Silver rod and
rod rotater
Connections to
microwave emission
and detection circuits
Fixed
mirror
Adjustable
mirror
To
vacuum
H2O-AgCl and H3N-AgCl
Side view
c
A
a
H2O-AgCl
rAg-Cl
O
Ag
r
M-O
H r
O-H
Cl
H3N-AgCl
c
a
H
H
N
rN-H
rM-N
Ag
• Near-prolate, asymmetric top.
• Dipole moment on a axis,
Expect a-type transitions.
• Sensitive to A, rM-Cl, rM-S.
• Cannot determine HOH, rO-H
rAg-Cl
Cl
• Prolate symmetric top.
• Dipole moment on a axis,
Expect a-type transitions.
• Sensitive to rM-Cl, rM-N.
• Cannot determine HNH, rN-H
H2O-AgCl
J′Ka′Kc′-J′′Ka′′Kc′′= 303-202
J′Ka′Kc′-J′′Ka′′Kc′′= 303-202
F′-F′′ = 5  3
2 2
F′-F′′ = 9  7
2 2
11510.0479 MHz
Exp.
4000 pulses
Exp.
Sim.
11,509.80
11512.0498 MHz
1000 pulses
Sim.
11,510.80
Frequency / MHz
11,511.80
Hyperfine structure arising from one
quadrupolar nucleus (Cl).
H2O-AgCl
J′Ka′Kc′-J′′Ka′′Kc′′= 303-202
Central components which have Ka=0
Components which
have Ka=1
Function of B0-C0
11,480
Components which
have Ka=1
11,500
11,520
Frequency / MHz
11,540
Low Barrier to Inversion in H2O-AgCl
39.1º
1000
800
3
V(φ)/cm-1
600
2
400
1
V=0
200
0
-80
-60
-40
-20
0
φ/deg
20
40
60
80
H2O-107Ag35Cl
H2O-109Ag35Cl
B0 + C0 / MHz
3837.23588(25)
3835.58849(25)
B0 - C0 / MHz
8.36795(15)
8.35936(15)
J / kHz
0.3834(48)
0.3823(48)
JK / kHz
39.90(7)
40.02(7)
-32.3193(29)
-32.319(29)
-0.498(15)
-0.519(15)
N
27
27
 / kHz
1.6
3.2
Cl / MHz
 aa
Cl
 bb
cc / MHz
aNumbers
in parentheses are one standard deviation in units of the last
significant figure.
• Fit spectra of 10
isotopologues with
a substitution at
every atom.
H3N-AgCl
J′-J′′ = 30-20
9 7
F1′-F1′′ = 
2 2
11649.5182 MHz
• Spectra of
isotopologues
containing 15N assigned
initially. Included;
H315N-107Ag35Cl,
H315N-109Ag35Cl and
H315N-107Ag37Cl
Exp.
Sim.
11,649.0
11,649.5
Frequency / MHz
11,650.0
H3N-AgCl
J′-J′′ = 30-20
F1′-F1′′, F′-F′′ =
9 7 9 7
 , 
2 2 2 2
9 7 11 9
 , 
2 2 2 2
7 5 5 3
 , 
2 2 2 2
Simulation multiplied by a
function which models power
distribution in the cavity.
Experimental Spectrum
7000 nozzle pulses
PGOPHER Simulation
(includes Doppler effect)
11,913.40
11,913.90
Frequency / MHz
11,914.40
H3N-AgCl
H315N-107Ag35Cl
H315N-109Ag35Cl
H314N-107Ag35Cl
1941.53295(39)
1940.65550(31)
1985.57609(16)
J / kHz
0.315(14)
0.319(12)
0.315*
JK / kHz
31.66(21)
31.95(17)
31.66*
/ MHz
-29.732(30)
-29.747(24)
-29.773(34)
/ MHz
-
-
-2.647(17)
9
9
9
2.1
1.6
2.8
B0 + C0 / MHz
Cl
 aa
 aaN
N
 / kHz
* Fixed at value for H315N107Ag35Cl
• 5 isotopes assigned including H314N-109Ag35Cl and H315N-107Ag37Cl
• Assignment of silver isotopes confirmed using isotopically-enriched
107Ag.
Molecular Structure
Ligand
Bond
0.9625
r=O-H
0.9602
[0.960]
H2O-AgCl
(cc-pVTZ)
(cc-pVQZ)
Exp. (r0)
2.226
14NH -AgCl
3
2.1619 1.0140
r=N-H
2.1530 1.0129
2.154 [1.013]
(cc-pVTZ)
(cc-pVQZ)
Exp. (r0)
Free AgCl
(re)
2.210
2.198
rAg-Cl
O
rM-O Ag
H r
O-H
Basis Functions
Main group atoms: cc-pVTZ and cc-pVQZ
Ag: cc-pVTZ-PP and cc-pVQZ-PP
Cl : cc-pV(T+d)Z and cc-pV(Q+d)z
David Tew and Jeremy Harvey, University of
Bristol.
M-L
A
a
CCSD(T) calculations using MOLPRO
c
Cl
c
a
H
H
N
rN-H
rM-N
Ag
rAg-Cl
Cl
2.280
LMCl MLH
178
115
HLH
105
315 1.901 1.896
J’-J’’
=3-2
11391
2.272
2.272
179
116
[180] 119
106
[105]
331 1.920 1.914
1.923 1.914
11502
11512
189 1.967 1.967
11805
189 1.981 1.981
1.986 1.986
11889
11914
M-Cl
2.2783
A
112
2.2714
112
2.267 [180] [112]
2.281
[107]
B
C

Cl
aa
Comparison
Cl 35
[  aa
( Cl)] / MHz
a.
b.
c.
d.
e.
f.
AgCla
-36.4
Ar-AgCla
-34.5
Kr-AgClb
-33.8
H2O-AgClc
-32.3
Xe-AgCld
-32.2
H3N-AgCle
-29.7
H2S-AgClc
-29.5
OC-AgClf
-28.2
C.J. Evans et al., J. Chem. Phys. 112, 1321 (2000)
J.M. Michaud et al., Inorg. Chem. 43, 3871 (2004)
S.J. Harris et al., Angew. Chem. Int. Ed., 49, 181 (2010)
S.A. Cooke et al., Phys. Chem. Chem. Phys. 6, 3248 (2004)
This work.
N.R. Walker et al., Inorg. Chem. 40, 6158 (2001)
Conclusions
• In H2O-AgCl, observed a structure that is effectively C2v or Cs with a very low
barrier to inversion. Determined rAgCl, rAgO distances and the angle between the
plane of the H2O molecule and the axis defined by the heavy atoms (r0 structure).
• In H3N-AgCl, observed a C3v geometry. Determined rAgCl and rAgO distances in an
Cl
N
r0 structure. Determined  aa and  aa
Acknowledgments
Financial Support
Felicity J. Roberts
Susanna L. Stephens
Anthony C. Legon
Victor A. Mikhailov
Stephanie J. Harris
David P. Tew
Jeremy N. Harvey
Engineering and Physical
Sciences Research
Council
Colin M. Western – work developing PGOPHER for microwave spectroscopy. (Talk on
Tuesday at 8:47 a.m., McPherson Lab., TC02).