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Water Solvation of Copper Hydroxide
Brett Marsh-UW Madison
Background
Copper
Catalytic
Relatively cheap
Abundant
CuOH-Possible water splitting catalyst
Experiment
ElectrosprayNeedle
Cryogenic ion trap (10K)For cooling and H2-tagging
Ion steeringoptics
Flight TubeReflectron
Tunable infrared laser
600-4500 cm-1
CapillarySkimmer
Radio-frequencyion guides
Ion reaction cell LN2 cooled
(77-350K)
Spectroscopylaser
Pulsed valves
Ion Trapping and Tagging
H2 has ideal binding energy (~400 cm-
1 typically) and vapor pressure at trap
temperature (10 K)
H2 tagging may produce multiply tagged species
M.Z. Kamrath, R.A. Relph, T.L. Guasco, C.M. Leavitt, M.A. Johnson, Int. J. Mass. Spec. 2011, 300, 91-98
Predissociation Spectroscopy
E. Garand et. al. Phys. Chem. Chem. Phys., 2012,14, 10109–10113
Experiment
ElectrosprayNeedle
Cryogenic ion trap (10K)For cooling and H2-tagging
Ion steeringoptics
Flight TubeReflectron
Tunable infrared laser
600-4500 cm-1
CapillarySkimmer
Radio-frequencyion guides
Ion reaction cell LN2 cooled
(77-350K)
Spectroscopylaser
Pulsed valves
ResultsBy varying voltages in ion source multiple species of interest can be selected for study
Results-CuOH(H2O)+
Addition of 2nd deuterium tag distorts spectrum
Strong H2O-D2 interaction?
Multiple conformations for 1 tag complex?
Results-CuOH(H2O)+
CAM-B3LYP/6-311+G(d,p) level of theory
Results-CuOH(H2O)2+
Severe peak suppression occurs after attachment of 2nd deuterium molecule
Possible solvent assisted isomerization?
Results-CuOH(H2O)2+
Isomers separated by~1450 cm-1
Multiple lines hidden under same peak?
Probe for H-bond stretches (2800-3100 cm-1)
CAM-B3LYP/6-311+G(d,p) level of theory
Solvent Assisted Isomerization
Excess solvation energy (in this case from D2) can push the molecule into a more stable well
Excess D2 then evaporates to leave isomer 2+2D2
Results-CuOH(H2O)2+
Strong free H2O interaction withD2 tag
Theory matches well with experimentalspectrum
CAM-B3LYP/6-311+G(d,p) level of theory
Results-CuOH(H2O)2+
CAM-B3LYP/6-311+G(d,p) level of theory
Results-CuOH(H2O)3+
Addition of 2nd deuterium tag seems to have no effect on spectrum
Conclusions
Hydrogen tags can not be assumed to offer little perturbation in metal species
Attachment of tags may distort the isomeric composition of ions of interest
Future Work
ElectrosprayNeedle
Cryogenic ion trap (10K)For cooling and H2-tagging
Ion steeringoptics
Flight TubeReflectron
Tunable infrared laser
600-4500 cm-1
CapillarySkimmer
Radio-frequencyion guides
Ion reaction cell LN2 cooled
(77-350K)
Spectroscopylaser
Pulsed valves
Tunable infrared laser
600-4500 cm-1
Acknowledgements
Crim Group
Garand Group
University of Wisconsin Chemistry Department