The Inorganic, Bioinorganic, and Organometallic Chemistry Program supports research in the mechanisms of bioinorganic chemistry. This project is a study of the mechanisms of heme-catalyzed oxidations. The reactions of various forms of oxygen, e.g., dioxygen, hydrogen peroxide, superoxide ion, and peracids, with iron porphyrins in biological systems are fundamental to oxygen metabolism, drug detoxification, steroid biosynthesis, and removal of hydrogen perioxide from living systems. Additionally, these metalloporphyrin systems constitute potentially important industrial oxidation catalysts. The model compounds under study are related to the hemin enzymes horseradish peroxidase, cytochrome peroxidase, catalase, chloroperoxidase, cytochrome P-450, and perhaps cytochrome oxidase. The goal is to mimic the rapid, high-turnover catalytic reactions catalyzed by these enzymes and consequently to develop new catalyst systems for synthetic oxidations. The project involves the design and preparation of new catalysts and the detailed studies of all of the steps involved in the metalloporphyrin-catalyzed epoxidation of alkenes, hydroxylation of alkanes, oxidations of arenes and phenols, and the decompositon of hydrogen peroxide and hydroperoxides. Kinetics and mechanisms of the formation of intermediate high-valent states and of their reactions with substrates will be investigated. In addition, the utilization of dioxygen in such reactions will be studied.
