Dinuclear Mn complexes as functional models of Mn catalase

Abstract

Phenoxo-bis(μ-carboxvlato)dimansanese complexes with a core structure of Cssymmetry show a high catalytic activity to disproportionate H2O2 (2H2O2 —» 2H2O + O2), whereas complexes with a core structure of C2 symmetry and mononuclear Mn complexes show only a low activity. For the Cssymmetric complexes, a dinuclear cw-{MnIV(=O)}2 intermediate has been detected in the H2o2disproportionation reaction and a mechanistic scheme to catalyze the H2o2disproportionation through the interconversion cw-{MnIV(=O) }2/cis-{MnIII(OH)} 2 is proposed. It is shown that the equivalence of two Mn ions in electronic nature is essential to show a CAT-like activity. © 1995 IUPAC