04/05/18 - 9:45 AM to 11:00 AM
Dow Lecture Series: Professor Christine Thomas
Dow Lecture Series
"New Frontiers in the Metal-Metal Bonding and Reactivity of Early/Late Heterobimetallic Complexes"
Bridging phosphinoamide ligands have been used to investigate early/late heterobimetallic complexes. The metal-metal interactions in these compounds provide a unique method for tuning redox potentials and promoting multielectron bond activation processes. For example, a representative tris(phosphinoamide)-supported Zr/Co complex was shown to undergo two-electron reduction at a potential 1 V more positive than a monometallic Co tris(phosphine) analogue. Once reduced by two electrons, the resulting coordinatively unsaturated Zr/Co complexes have been shown to undergo one-, two-, and four-electron transfer processes, activating a wide variety of sigma bonds (e.g. O-H, N-H, C-X) and pi bonds (e.g. the C=O bond in CO2 or ketones). The unique reactivity of heterobimetallic complexes has been applied to several catalytic processes, including Kumada cross-coupling and the hydrosilylation of ketones and aldehydes, and it has been demonstrated that both metal centers play a crucial role in catalysis. An expanded series of heterobimetallic compounds has been synthesized, uncovering metal-metal multiple bonds and unique reactivity patterns across a variety of different metal-metal combinations.
Professor Thomas' research group is interested in fundamental catalysts design principles involving (1) two metal centers in bimetallic frameworks and (2) metal centers and non-innocent ligands, and the unique effects that such cooperation can have on the reactivity of these species. All projects in Thomas' group entail the synthesis of new ligands and transition metal complexes. Although the primary focus of the research is synthesis, the research pursued also entails a large variety of characterization techniques including single crystal X-ray diffraction, multinuclear NMR, IR, UV-Vis, Mössbauer and EPR spectroscopies, as well as magnetic and electrochemical measurements using SQUID magnetometer and cyclic voltammetry. In addition, theoretical investigations into the electronic structure and reactivity of particularly interesting transition metal complexes synthesized in the lab are studied using density functional theory calculations using computational software including Gaussian and ORCA.
Professor Thomas received her Bachelor of Science in chemistry from Lafayette College (Easton, PA) in 2001, where she worked on the synthesis and electrochemistry of inorganic compounds with Professor Chip Nataro. She received her doctorate in inorganic chemistry in 2006 at the California Institute of Technology (Pasadena, CA), under the direction of Professor Jonas C. Peters. Her graduate research focused on a range of synthetic projects related to inorganic and organometallic chemistry, including the examination of C-H activation by platinum complexes, the design of new ligands, the examination of the reactivity of coordinatively unsaturated tris(phosphino)borate iron complexes towards small molecule activation, and the synthesis of the first well-defined and structurally characterized Fe(IV) imido complex. Thomas went on to pursue post-doctoral work under the direction of Professors Marcetta Y. Darensbourg and Michael B. Hall at Texas A&M University (College Station, TX), where her post-doctoral research concentrated on the experimental and theoretical investigation of small molecule models of the dinuclear active site of [FeFe]-Hydrogenase, an enzyme that catalyzes the reversible production of hydrogen from protons. In 2008, Thomas began her career as an assistant professor of chemistry at Brandeis University (Waltham, MA).
She was selected for Department of Energy's Early Career Research Program in 2011, was named a 2011 Alfred P. Sloan Fellow, and received a National Science Foundation CAREER award in 2012. She was selected as a 2012 Organometallics Fellow, was named a 2013/2014 Chemical Communications Emerging Investigator, was named a Fellow of the Royal Society of Chemistry in 2014, and was selected for the 2015 Dalton Transactions Lectureship. Professor Thomas' dedication to teaching has also been recognized by the 2012 Michael L. Walzer '56 Award for Excellence in Teaching at Brandeis University.
At Brandeis University, Thomas was promoted to associate professor with tenure in May 2013 and to full professor in July 2016. She has been on the Editorial Advisory Board of Chemical Communications since 2012, is on the Board of Directors of Inorganic Syntheses, and has been serving as an associate editor of Dalton Transactions since 2014. Thomas joined the Department of Chemistry and Biochemistry at Ohio State University in January 2018.