The Que group focuses on bio-inorganic chemistry, specifically on the topic of iron, oxygen and biocatalysis. Our research efforts, involving a combination of biochemical, synthetic inorganic, and spectroscopic approaches, are aimed at understanding the oxygen activation mechanisms of nonheme iron enzymes, designing functional models for such enzymes, trapping and characterizing reaction intermediates, and developing bio-inspired oxidation catalysts for green chemistry applications. Targets include methane monooxygenase and related diiron enzymes, as well as monoiron enzymes with a common 2-His-1-carboxylate facial triad active site, including enzymes that require alpha-keto acids as co-substrates, Rieske dioxygenases that carry out cis-dihydroxylation of arene double bonds, and a novel pair of Fe- and Mn-dependent catechol dioxygenases. Intermediates of prime interest are high-valent oxoiron species thought to be carry out the most challenging oxidative transformations. The picture shows the crystal structure of an oxoiron(IV) complex we have characterized, such as the hydroxylation of methane and the conversion of water to O2.
