IRON COMPLEXES AS FUNCTIONAL MODELS FOR THE SOLUBLE METHANE MONOOXYGENASE ENZYME

Abstract

Oxygen activation by nonheme diiron enzymes occurs in numerous metabolically important transformations, including those by soluble methane monooxygenase (sMMO), ribonucleotide reductase (RNR), fatty acid desaturases, human deoxyhypusine hydroxylase, etc. During the activation of O2 the diiron(II) center is transformed to a peroxodiiron(III) intermediate that in turn converts to the oxidizing species. This intermediate typically exhibit visible features between 600-750 nm and resonance Raman (rRaman) features associated with a (mu-1,2-peroxo)diiron(III) unit. Studies of synthetic complexes that mimic O2 activation can complement and augment the information available from enzyme studies. Complexes for which intermediates along the O2-activation pathway can be traced are particularly useful. We report here the spectroscopic characterization of peroxo-intermediates derived from the reaction of H2O2 with Fe(II) complexes of rigid N-donor ligands. Investigations into their catalytic reactivity with H2O2 were performed on the oxidation of sulfides, alcohols and C-H compounds