Concerted proton-coupled electron transfers in aquo/hydroxo/oxo metal complexes: electrochemistry of [OsII(bpy)2py(OH2)]2+ in water.

ABSTRACT: Kinetic analysis of the successive oxidative cyclic voltammetric responses of [Os(II)(bpy)(2)py(OH(2))](2+) in buffered water, together with determination of H/D isotope effects, has allowed the determination of the mechanisms of the successive proton-coupled electron transfers that convert the Os(II)-aquo complex into the Os(III)-hydroxo complex and the later into the Os(IV)-oxo complex. The stepwise pathways prevail over the concerted pathway in the first case. However, very large concentrations of a base, such as acetate, trigger the beginning of a concerted reaction. The same trend appears, but to a much larger extent, when high local concentration of carboxylates are attached close to the Os complex. The Os(III)-hydroxo/Os(IV)-oxo couple is globally much slower and concerted pathways

SUBMITTER: Costentin C 

PROVIDER: S-EPMC2715510 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature