Taking Hold of Iron Oxidation

Abstract

CHEMISTRY Both heme and nonheme iron enzymes can oxidize C-H bonds. For the oxidation of such bonds in cyclohexane, it is believed that an Fe(IV)=O species affects this transformation. It has been unclear whether a similar one-electron-reduced species in a non-heme ligand environment would be able to oxidize stronger C-H bonds. Previous studies have shown that Fe(IV) complexes stabilized with tetradentate N4 ligands could perform atom transfer reactions; for example, the tripodal ligand tris(2-pyridylmethyl)amine can epoxidize the double bond of cyclooctene. Kaizer et al . show that two different pentadentate N5 ligands form Fe(IV)=O complexes that are able to hydroxylate the C-H bonds in cyclohexane and are stable enough to perform this reaction at room temperature. These findings support mechanisms that invoke the Fe(IV)=O intermediates in mononuclear nonheme iron enzymes. — PDS J. Am. Chem. Soc . 10.1021/ja037288n (2003).