Marcetta Y. Darensbourg

Texas A&M University-College Station


Primary Section: 14, Chemistry
Membership Type:
Member (elected 2017)

Biosketch

Marcetta York Darensbourg is an inorganic/organometallic chemist whose earlier synthetic expertise and mechanistic studies of low valent transition metal hydrides have evolved into current efforts towards the development of synthetic analogues of enzyme active sites that contain metal-carbon bonds--especially the carbon monoxide- and cyanide-stabilized iron centers in hydrogenases that are known from spectroscopies and protein crystallography. Biomimetics are designed to reproduce key structural, spectroscopic and reactivity features of the natural organometallic catalysts that connect to the catalytic electrochemical mechanisms of these natural fuel cell catalysts, as well as carbon-carbon coupling processes as in acetyl-coA synthase. Marcetta is a native of Kentucky, with an undergraduate degree in chemistry from Union College, Barbourville KY, and a PhD in Inorganic Chemistry from the University of Illinois. Following academic posts at Vassar College and Tulane University, she joined the faculty at Texas A&M University, College Station, TX, in 1982. She holds the title of Distinguished Professor of Chemistry at TAMU and is a member of the American Academy of Arts and Sciences and the National Academy of Sciences; she is a fellow of the American Chemical Society and the Royal Society of Chemistry.

Research Interests

The well-known metals in biology on oxygen-rich Earth that govern life processes as biocatalysts in enzymes or as structural elements, are typically bound within complicated organic ligands by oxygen and nitrogen, sometimes sulfur, donors to the trace transition metal ions. As holdovers from an age when earth was under a reducing atmosphere, some enzymes in microorganisms that perform reductive reactions, contain iron, sometimes nickel, stabilized in low-valent states by simple diatomic molecules such as carbon monoxide and cyanide, and involve two metals bridged by sulfur. Marcetta Darensbourg, her group and her collaborators design, synthesize and characterize inorganic/organometallic compounds that mimic the active sites of hydrogenases; they uncover molecular features critical to structure and function of these evolutionarily perfected biocatalysts for hydrogen metabolism. Such small molecular models, even without the protein superstructure, show some activity as electrocatalysts for the hydrogen evolution reaction, fulfilling a goal in base metal catalysis involving metal hydrides. Nature’s control of the diatomics, CO and cyanide, obviates a poisoning effect on the microorganism host, and suggests their genesis on iron. Applying the tenets and principles of organometallic chemistry, the group explores another poisonous diatomic, nitric oxide, in dinitrosyl iron complexes produced from NO-overload from iron sulfur clusters.

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