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Research Abstracts Online
January 2009 - March 2010

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University of Minnesota Twin Cities
Institute of Technology
Department of Chemistry

PI: Lawrence Que, Jr.

Spectroscopic and Computational Investigations of Biomimetic Iron Complexes Relevant to Oxygen-activating Nonheme Iron Enzymes

Oxygen-activating iron enzymes having mono- or di-nuclear active sites are known to utilize dioxygen to create highly reactive enzyme active sites that carry out site-specific C–H bond activation. For example, in the diiron enzyme methane monooxygenase, a high-valent reactive intermediate, Q, oxidizes methane to methanol, beginning the first step in carbon utilization for methanotrophic bacteria. Likewise, in the mononuclear iron enzyme, AlkB, a high-valent iron center is implicated in demethylation of nucleotides in DNA and RNA repair. These two examples of iron enzymes that utilize dioxygen to carry out seemingly "simple” reactions are unmatched in the laboratory, where "harsher” chemical conditions are needed. Studying small-molecule (di)iron complexes is essential for understanding the electronic and mechanistic pathways for oxygen activation by these enzymes. This group utilizes spectroscopic methods such as UV-vis, x-ray adsorption, Mössbauer, resonance Raman, and electron paramagnetic resonance spectroscopies to define the electronic properties of these model complexes and understand how and why (di)iron enzymes carry out these chemical reactions. Computational methods are used to predict structural, electronic, and magnetic properties of these model complexes to aid in the interpretation of the experimental data.

Group Members

Matthew Cranswick, Research Associate
Adam Fiedler, Research Associate
Kathy Van Heuvelen, Research Associate