Chemical Society Seminar: Dr. Tim Storr - Electronic Structure and Reactivity of Oxidized Metal Phenoxides

The interplay of redox-active transition metal ions and pro-radical ligands in metalloenzyme sites has generated considerable interest. The Cu(II)-phenoxyl radical form of galactose oxidase, as well as the Fe(IV)=O porphyrin radical intermediate of P450 enzymes are principal examples. Both of these enzymatic systems have inspired efforts to develop small molecule mimics capable of mild and selective oxidation chemistry. Recent developments show that ligands serving as electron reservoirs offer opportunities to expand catalysis, especially by conferring to first-row transition metals a “noble metal-like” reactivity.[1] We have extensively investigated the chemistry of a series of oxidized mono- and bis-phenoxide metal complexes, which demonstrate that small variations of the ligand structure affect the oxidation locus. Characterization of oxidized species by both experimental and theoretical methods has afforded significant information about the electronic structure of these ligand radical systems. Building on this work, recent studies with a series of oxidized nitridomanganese(V) salen complexes demonstrate that nitride activation is dictated by remote ligand electronics.[2] We are currently investigating the reaction mechanism and further applications of this chemistry. 

1.       P. J. Chirik and K. Wieghardt, Science, 2010, 327, 794.

2.       R. M. Clarke and T. Storr, J. Am. Chem. Soc. 2016, 138, 15299