Inorganic Models for Two-Electron Redox Chemistry in Biological Systems Ligand-Bridged Molybdenum and Tungsten Dimers

Abstract

We describe the energetics of concerted two-electron transfer and metal-metal bond cleavage in the sulfido- and phosphido- bridged dimers [M 2(μ-ERn)2(CO)8]0/2- (M = Mo or W; RnE- = RS- or R2P -). Reduction of the neutral dimers to their corresponding dianions occurs in a single two-electron step accompanied by cleavage of a metal-metal single bond and large changes in the M-M distance and M-E-M and E-M-E bridge angles. These structural reorganizations provide the driving force for concerted two-electron transfer via inversion of the 0/- and -/2- redox poten