Photoelectron Spectroscopy of Group VI transition Metal oxygen clusters
EMSL Project ID
2266
Abstract
This proposal outlines possible experiments to be carried out during a visit by Tom Waters (Melbourne University, Australia) to PNNL during November 2001 to work with Professor Lei-Sheng Wang. This visit would make use of the magnetic-bottle time-of-flight photoelectron spectrometer currently in use at PNNL. The two broad classes of anions encompassed in this proposal are outlined below. (i) The small dimolybdate dianion, [MoVI2O7]2-, and related species. Electrospray Ionisation (ESI) of tetra-alkylammonium salts of [Mo2O7]2- in MeCN allow the dimolybdate anion to be transferred to the gas phase. We have recently shown that [Mo2O6(OCH3)]- (related to the dimolybdate anion) is able to catalyse the gas phase oxidation of methanol to formaldehyde (see attached Figure 1, also: Waters, T., OHair, R.A.J., Wedd, A.G., Chemm. Commun., 2000, 225). Proposed PES experiments will focus on ions relevant to this catalytic cycle and other related novel ions that can be generated via ESI. (ii) Mononuclear models for the molybdenum and tungsten containing enzymes Mononuclear molybdenum and tungsten containing enzymes are able to catalyse the net transfer of an oxygen atom between a substrate and water (e.g DMSO reductase, Me2SO + 2e- + 2H+ ? Me2S + H2O). Many synthetic analogues of these enzymes have been prepared in an effort to mimic their chemical and spectroscopic properties. These model compounds include doubly charged anions such as [MoVIO2(mnt)2]2-, [MoIVO(mnt)2]2-, [WVIO2(mnt)2]2- and [WIVO(mnt)2]2- (mnt = [S2C2(CN)2]2-). PES experiments proposed for these systems will focus on; (i) comparisons between analogous oxidised and reduced forms; and (ii) comparisons between equivalent redox states with different metal centres.
Project Details
Project type
Exploratory Research
Start Date
2001-11-05
End Date
2004-11-07
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Waters T, XB Wang, X Yang, LY Zhang, LS Wang, AG Wedd, and RA O'Hair. 2004. "Photoelectron Spectroscopy of the Doubly-Charged Anions [MIVO(mnt)2]2- (M=Mo, W; mnt=S2C2(CN)22-): Access to the Ground and Excited States of the [MvO(mnt)2]-Anion." Journal of the American Chemical Society 126(16):5119-5129.
Water T, XB Wang, and LS Wang. 2007. "Electrospray Ionization Photoelectron Spectroscopy: Probing the Electronic Structure of Inorganic Metal Complexes in the Gas-Phase." Coordination Chemistry Reviews 251(3-4):474-491.