Electrochemically controlled dissociation of dioxygen from a μ-peroxo cobalt(III) dimer

The electrochemistry of the µ-peroxo dimer of a cobalt Schiff-base complex, [{Co^III(salen)(dmso)}₂O₂][salen = N,N'-ethylenebis(salicylideneiminate), dmso = dimethyl sulfoxide], has been studied in solution in dmso. Controlled-potential oxidative electrolysis of the dimer is a two-electron process and resulted in its dissociation, with release of dioxygen to the solution and formation of [Co^III(salen)(dmso)₂]⁺. Reduction of the cobalt(III) complex produced the corresponding cobalt(II) complex. The various redox and co-ordination states of the process were characterised by spectroelectrochemistry. The results provide conclusive evidence that electrochemical oxidation can be used as a mechanism for release of O₂ from a dioxygen-containing complex.