Transcript Ohio_2010_H2OCuCl.pptx

1
Microwave Spectra and Structures of
H2S-CuCl and H2O-CuCl
by
Nicholas R. Walker, Felicity J. Roberts, Susanna L. Stephens,
David Wheatley, Anthony C. Legon
Rod
rotator
Laser
arm
Gas line
attached
to solenoid
valve
Microwave emission
antenna
H
O
Cu
Cl
Objectives
• Apply microwave spectroscopy to study interactions of the broadest
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-CuCl, H2O-CuCl 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
Adiabatic expansion of CCl4 / H2O / Ar
Gas line
Copper rod and
rod rotater
Connections to
microwave emission
and detection circuits
Fixed
mirror
To
vacuum
Adjustable
mirror
Side view
a
O
H
rO-H
A
rM-O Cu
H2O-CuCl
c
rCu-Cl
Cl
• Near-prolate, asymmetric
top of Cs symmetry.
• Dipole moment on a axis,
Expect a-type transitions.
c
End view
•
c-type transitions outside
the operating range of the
spectrometer.
• Sensitive to A, rM-Cl, rM-S.
b
θHOH
• Cannot determine HOH, rO-H
H2O-CuCl
JKaKc′-JKaKc′′ =3-2
~14600 MHz
JKaKc′-JKaKc′′ =2-1
~9700 MHz
6,000
8,000
B0  C0
10,000
12,000
14,000
Frequency / MHz
16,000
18,000
J′Ka′Kc′-J′′Ka′′Kc′′= 303-202
7 7
F1′-F1′′, F′-F′′ =  , 3-2
2 2
14610.452 MHz
H2O-CuCl
~10 kHz
J′Ka′Kc′-J′′Ka′′Kc′′= 202-101
1400 gas pulses
Exp.
F1′-F1′′, F′-F′′ = 7  5 , 2-1
2 2
9740.172 MHz
9740.255 MHz
F1′-F1′′, F′-F′′ = 7  5 , 4-3
2 2
Sim.
14610.1
14610.3
14610.5
8000 gas pulses
Frequency / MHz
Exp.
Sim.
9740.05
9740.25
Frequency / MHz
9740.45
J′Ka′Kc′-J′′Ka′′Kc′′= 312-211
F1′-F1′′, F′-F′′ = 9  7 , 5-4
2 2
~20 kHz
14631.505 MHz
2000 gas pulses
Exp.
Sim.
14631.1
14631.3
Frequency / MHz
Ka=1
14631.5
H2O-CuCl
Hyperfine structure arising from two
quadrupolar nuclei (Cu, Cl).
Central components which have Ka=0
JKaKc′-JKaKc′′ =3-2
Components which
have Ka=1
Function of B0-C0
14580
14600
14620
Frequency / MHz
Components which
have Ka=1
14640
39.1º
1000
800
3
V(φ)/cm-1
600
2
400
1
V=0
200
0
-80
-60
-40
-20
0
20
40
60
80
φ/deg
“Identification and molecular geometry of a weakly bound dimer (H2O,HCl)
in the gas phase by rotational spectroscopy”
A. C. Legon and L. C. Willoughby, Chem. Phys. Letters, 95, 449-52, (1983).
4000
3000
2000
V(φ)/cm-1
5
3
1000
4
2
1
V=0
0
-120
-90
-60
-30
0
φ/deg.
30
60
90
120
H2O-63Cu35Cl
B0 + C0 / MHz
B0 - C0 / MHz
4868.9709(9)
13.04641(48)
H2O-65Cu35Cl
4865.5423(10)
13.02037(65)
J  103 / kHz
0.551(28)
0.518(31)
JK  103 / kHz
63.96(19)
64.25(27)
50.2830(85)
46.500(27)
-11.702(48)
-10.84a
-25.497(12)
-25.5013(75)
-0.808(34)
-0.808a
/ kHz
17.2(59)
17.2b
/ kHz
17.67(71)
17.67b
Cu
/ MHz
 aa
Cu
/ MHz
 bb
cc
Cl
 aa
/ MHz
Cl
 bb
cc / MHz
Cu
Caa
Cu
Cbb
aFixed
• 10 isotopologues
studied including
substitutions at every
atom.
• 47 F′-F′′ transitions
measured for H2O63Cu35Cl isotopologue,
standard deviation of
fit = 3.2 kHz.
at value for H2O-63Cu35Cl multiplied by ratio of nuclear quadrupole moments for the copper (65Cu/63Cu)
isotopes.
bFixed at value for H O-63Cu35Cl.
2
cNumbers in parentheses are standard deviation in units of last significant figure.
Structure Determination
H2O-CuCl
H2S-CuCl
CuCl
rCu-Cl / Å
2.059(4)
2.0631(3)*
2.051 (re)
rCu-L / Å
1.918(8)
2.1532(3)*
-
/˚
39.8(11)
73.956(15)*
-
*No isotopic substitution available at sulphur atom.
Side view
A
a
O r
Cu
M-O
H
rO-H
c
rCu-Cl
Cl
Conclusions
• Microwave spectrum of H2O-CuCl assigned and structure determined.
• Molecule is either C2v planar at equilibrium or the potential energy barrier to
inversion is low enough that the v=0 and 1 states (associated with inversion
of the water molecule) are well separated.
Acknowledgments
Financial Support
Felicity J. Roberts
Susanna L. Stephens
Anthony C. Legon
Victor A. Mikhailov
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).