title: Sulfur K-edge XAS of WVO vs. MoVO bis(dithiolene) complexes: contributions of relativistic effects to electronic structure and reactivity of tungsten enzymes.
abstract: Molybdenum- or tungsten-containing enzymes catalyze oxygen atom transfer reactions involved in carbon, sulfur, or nitrogen metabolism. It has been observed that reduction potentials and oxygen atom transfer rates are different for W relative to Mo enzymes and the isostructural Mo/W complexes. Sulfur K-edge X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations on [Mo(V)O(bdt)(2)](-) and [W(V)O(bdt)(2)](-), where bdt=benzene-1,2-dithiolate(2-), have been used to determine that the energies of the half-filled redox-active orbital, and thus the reduction potentials and MO bond strengths, are different for these complexes due to relativistic effects in the W sites.
authors.affiliation: Department of Chemistry, Stanford University, USA.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Tenderholt
authors.forename: Robert K
authors.initials: RK
authors.lastname: Szilagyi
authors.forename: Richard H
authors.initials: RH
authors.lastname: Holm
authors.forename: Keith O
authors.initials: KO
authors.lastname: Hodgson
authors.forename: Britt
authors.initials: B
authors.lastname: Hedman
authors.forename: Edward I
authors.initials: EI
authors.lastname: Solomon
mesh_terms: D015502:Absorptiometry, Photon; D004798:Enzymes / Q000737:chemistry* / Q000378:metabolism; D015394:Molecular Structure; D008982:Molybdenum / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D013455:Sulfur / Q000737:chemistry*; D013816:Thermodynamics; D014414:Tungsten / Q000737:chemistry*
chemical_list: D004798:Enzymes; D009942:Organometallic Compounds; C418404:bis(dithiolene)molybdenum (IV); C418405:bis(dithiolene)tungsten; D013455:Sulfur; D008982:Molybdenum; D014414:Tungsten