The kinetics of the oxidation of hydrogen peroxide by bis(2,2′-bipyridine)manganese(III) ions in aqueous perchlorate media

Abstract

The kinetics of the oxidation of hydrogen peroxide by bis(2,2′-bipyridine)manganese(III) ions have been investigated in aqueous perchlorate media. The kinetics are found to vary with the initial ratio [H₂O₂]/[Mn(bipy)³⁺_2aq·]: if k₀ is the observed pseudo-first-order rate constant, linear plots are found for k^–1₀ against [H₂O₂]^–1 at low [H₂O₂] and linear plots of k₀ against [H₂O₂] with an intercept on the k₀ axis are found at high [H₂O₂]. From a detailed consideration of the variation of the kinetics with [H₂O₂] and [H⁺], the first-order decomposition of three complexes, [Mn(bipy)₂HO₂]²⁺_aq·, [Mn(bipy)₂(H₂O₂)₂]³⁺_aq· and [Mn(bipy)₂H₂O₂HO₂]²⁺_aq· are found to contribute to the oxidation.