Nonheme Iron Centers in Oxygen Activation: Characterization of an Iron(III) Hydroperoxide Intermediate

A new pentadentate nitrogen ligand facilitates the synthesis of a low-spin iron(II) complex, which reacts with H2O2 at low temperature to form the transient purple complex 1. Complex 1 was formulated as an FeIIIOOH complex, the first synthetic example of such a species to be characterized by electrospray ionization mass spectrometry. Furthermore, 1 oxidizes cyclohexane efficiently, thus supporting the notion that an FeIIIOOH moiety can participate in oxygen activation mechanisms of nonheme iron enzymes.