The role of carboxylato ligand dissociation in the oxidation of chrysin with H2O2 catalysed by [Mn2III,IV(μ-CH3COO)(μ-O)2(Me4dtne)](PF6)2

Abstract

The aqueous and non-aqueous chemistry of the complex [Mn₂^III,IV(μ-CH₃COO)(μ-O)₂(Me₄dtne)](PF₆)₂ (where Me₄dtne = 1,2-bis(4,7-dimethyl-1,4,7-triazacyclonon-1-yl)ethane), which has been demonstrated as an exceptionally active catalyst in the bleaching of raw cotton and especially wood pulp at high pH (>11), is explored by UV/vis absorption, Raman and EPR spectroscopies and cyclic voltammetry. The data indicate that dissociation of the μ-acetato bridge is essential to the catalyst activity and rationalises the effect of sequestrants such as DTPA on its performance.