Kinetics of the oxidation of hydrogen peroxide by the tris(2,2′-bipyridine)nickel(III) ion in aqueous perchlorate media: comparison with oxidation by aqua-cations

Abstract

A complex [Ni(bipy)₃]³⁺ has been prepared by the electrolytic oxidation of [Ni(bipy)₃]²⁺. The kinetics of the oxidation of hydrogen peroxide by this complex in aqueous perchlorate media over a temperature range 3.0–40 °C using both conventional and stopped-flow spectrophotometry show that the reaction is first order in [Ni(bipy)₃³⁺], first order in [H₂O₂], and zero order in [H⁺]. No intermediate complexes are detected, and the zero order in [H⁺] shows that the oxidation is not preceded by the substitution of H₂O₂ into the inner sphere of Ni³⁺. This oxidation is compared with the reaction of H₂O₂ with highly oxidizing aqua-cations.