Ligand topology effect on the reactivity of a mononuclear nonheme iron(IV)-oxo complex in oxygenation reactions

Abstract

Mononuclear nonheme iron(IV)-oxo complexes with two different topologies, cis-α-[Fe IV(O)(BQCN)] 2+ and cis-β-[Fe IV(O)(BQCN)] 2+, were synthesized and characterized with various spectroscopic methods. The effect of ligand topology on the reactivities of nonheme iron(IV)-oxo complexes was investigated in C-H bond activation and oxygen atom-transfer reactions; cis-α-[Fe IV(O)(BQCN)] 2+ was more reactive than cis-β-[Fe IV(O)(BQCN)] 2+ in the oxidation reactions. The reactivity difference between the cis-α and cis-β isomers of [Fe IV(O)(BQCN)] 2+ was rationalized with the Fe IV/III redox potentials of the iron(IV)-oxo complexes: the Fe IV/III redox potential of the cis-α isomer was 0.11 V higher than that of the cis-β isomer. © 2011 American Chemical Society.