George A. and Hilda M. Daubert Professor of Chemistry (b. 1932)
B.S., 1954, University of Nebraska; M.S., 1956; Ph.D., 1958, University of Illinois
ACS Award in Inorganic Chemistry, 1975; National Academy of Sciences, 1975; American Academy of Arts and Sciences, 1975; Guggenheim Fellow, 1977-78 and 1985-86; California Scientist of the Year Award, 1983; ACS Arthur C. Cope Scholar Award, 1986; ACS (Puget Sound and Oregon Section) Pauling Award, 1990; ACS Award for Distinguished Service in the Advancement of Inorganic Chemistry, 1991; John C. Bailar Jr., Medalist, 1995; ACS Alfred Bader Award in Bioinorganic or Bioorganic Chemistry, 1997
Inorganic, Organic, and Organometallic Chemistry
The catalysis of multi-electron redox reactions is a fundamental problem that has been solved in certain biological systems through the agency of multimetallic enzymes (cytochrome c oxidase, laccase, and nitrogenase). The detailed mechanisms by which these metalloenzymes function are still obscure. Our research is directed towards the synthesis of functional biomimetic catalysts for the electrochemical reduction of dioxygen to water (a 4e– process), nitrogen to ammonia (a 6e– process), and the oxidation of hydrogen (a 2e– process). Recently we have developed several functional models for the active site in cytochrome c oxidase. These complexes reduce O2 by 4e– at pH 7. The complex that is structurally closest to "the real thing", is the best catalyst. By studying the electrocatalytic reduction of dioxgen in lipid layers under conditions of slow electron delivery, we have shown that CuB is necessary to afford selective 4e– reduction of dioxygen at physiological potentials.
The enzyme family cytochrome P-450 catalyzes the incorporation of one oxygen atom from O2 into a variety of organic substrates. We are developing chiral porphyrin catalysts for asymmetric, catalytic oxygenation of olefins and hydrocarbons. We have also developed Fe porphyrins that have normal O2, but low CO affinities. We are exploring an alternative mechanism by hydrocarbon C-H oxygenation.
We are exploring the synthesis, structural characterization, spectroscopic properties (Raman, IR, NMR), electrochemistry, magnetic properties and chemical reactions of 4d and 5d metalloporphyrin dimers. These manifest the entire range of M-M bond orders: 1, 1.5, 2, 2.5, 3, 3.5, and 4. Recently we have prepared and structurally characterized multiple bonds between metals in different triads of the periodic table.