Evidence for a higher oxidation state of manganese in the reaction of dinuclear manganese complexes with oxidants. Comparison with iron based gif chemistry.

Binuclear manganese complexes mimic the catalase enzyme by converting hydrogen peroxide rapidly and efficiently to oxygen and water. The complex (1) may be activated by either periodic acid or Oxone(R) and can oxidize selected organic substrates. Potassium manganate gave similar oxidation products suggesting that the manganese is transformed to a higher oxidation state. Kinetic studies with the Mn-IV-Mn-IV complex show an induction period indicating that it is not the active catalyst. Further studies suggested that the actual catalytic species is a Mn-III-Mn-IV complex. These complexes show similar properties to the activation of FeCl3 with hydrogen peroxide. This is particularly evident by the formation of a new and unusual paroxide from ergosterol acetate. (C) 1998 Elsevier Science Ltd. All rights reserved.