title: Cations M2(O2CtBu)4+, where M = Mo and W, and MoW(O2CtBu)4+. Theoretical, spectroscopic, and structural investigations.
abstract: With the aid of density function theory, the molecular and electronic structures of the molecules Mo2(O2CMe)4, MoW(O2CMe)4, and W2(O2CMe)4 and their single-electron oxidized radical cations have been determined; this includes calculated observables such as v(MM) and the delta --> delta* electronic transition energies. The calculated properties are compared with those for the corresponding pivalates, M2(O2CtBu)4 (M = Mo or W) and MoW(O2CtBu)4 and their radical cations prepared in situ by oxidation with Cp2FePF6. The EPR spectra of the radical cations are also reported. The EPR spectrum of the MoW(O2CtBu)4+ cation reveals that the unpaired electron is in a polarized MM delta orbital having 70% Mo and 30% W character. The MM stretching frequencies show good correlation with the MM bond lengths obtained from single-crystal X-ray diffraction studies of MoW(O2CtBu)4, W2(O2CtBu)4, and W2(O2CtBu)4+PF6- compounds, along with previously reported structures. These data provide benchmark parameters for valence trapped dicarboxylate bridged radical cations of the type [(tBuCO2)3M2]2(micro-O2C-X-CO2)+ (X = conjugated spacer).
authors.affiliation: Department of Chemistry, The Ohio State University, Columbus, Ohio 43210-1185, USA. chisholm@chemistry.ohio-state.edu
authors.forename: Malcolm H
authors.initials: MH
authors.lastname: Chisholm
authors.forename: Jason S
authors.initials: JS
authors.lastname: D'Acchioli
authors.forename: Brian D
authors.initials: BD
authors.lastname: Pate
authors.forename: Nathan J
authors.initials: NJ
authors.lastname: Patmore
authors.forename: Naresh S
authors.initials: NS
authors.lastname: Dalal
authors.forename: David J
authors.initials: DJ
authors.lastname: Zipse