Mechanistic studies on oxidation of hydrogen peroxide and hydrazine by a metal-bound superoxide

► Mechanism of oxidation of H2O2 and N2H5+ by [(en)(dien)CoIII(O2)CoIII(en)(dien)]5+ is discussed. ► The observed base catalysis in the reactions appears to be a result of an electroprotic mechanism. ► Acid partly consumes superoxo complex forming kinetically dead-end species, incapable to accept proton from the reductants.