Cobalt complexes, electron-transfer reactions dimerization

The rhodium(II) radical [Rh(dmgH)2PPh3], formed by laser photolysis of the corresponding dimer, is oxidized by a range of cobalt(II) complexes which have coordinated halides. " Electron transfer is believed to occur through a ligand-mediated pathway and the reaction rate is dependent upon the choice of halide. In an examination of the Ti(III)-induced cyclization of epoxyolefins, a mechanism has been invoked which involves a metal-centered radical. ... 

In most cases cobalt complexes form a P Peroxo dimer with oxygen in water. Figure 2 shows this reaction together with the electrochemical reactions required to complete the cycle in the extraction system. It is clear that the anode reaction involves a two-electron cleavage reaction while the cathodic reaction involves a "simple electron transfer. Since the power consumed by the oxygen extraction system depends on the potential difference between the two reactions the factors which affect them are of practical as well as theoretical interest. 

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