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

摘要

We describe the energetics of concerted two-electron transfer and metal-metal bond cleavage in the sulfido- and phosphido-bridged dimers [M_2(μ-ER_n)_2(CO)_8]~(0/2-) (M = Mo or W; R_0E~- = RS~- or R_2P~-). 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 potentials.