Binuclear manganese redox enzymes,

This process is catalyzed by a variety of catalase enzymes, the most common being the heme catalases, which accomplish the two-electron chemistry of Eq. (12) at a mononuclear heme center. Here, both the iron and its surrounding porphyrin ligand participate to the extent of one electron each in the redox process. Manganese catalases contain a binuclear Mn center and cycle between Mn2(II,II) and Mn2(III,III) oxidation states while carrying out the disproportionation of H2O2. The enzyme can... 

The preparation and characterization of novel manganese (III) complexes of various porphyrin and porphyrin-likes macrocycles have continued to attract strong attention especially because of their importance in catalytical oxidation processes through the formation of a Mn(V)0 intermediate (see Section 6) and as model for metalloenzymes. In this line, an artificial enzyme formed through a directed assembly of a molecular square that encapsulated a Mn porphyrin has been prepared and investigated as a catalyst. In contrast to symmetrical binuclear bis(phenoxo) bridged macrocyclic Mn(III)Mn(III) complexes, unsymmetrical ones are rare. A new series of these kinds of carboxylate-free complexes has been described and their redox properties investigated. " ... 

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