Structure and Bonding in Transition Metal Compounds
Research Interests: The scientific approach of my research group is to discover new chemistry by systematic investigations of interesting and difficult problems of electronic structure. Projects typically combine one or more of the following themes: synthesis, spectroscopy, computations, photochemistry, catalysis, cryogenic techniques, magnetism, mechanisms, crystallography, bonding, and reactivity. A major goal is for my coworkers to become proficient in several of these areas while gaining an appreciation of all of the other areas.
Current research in my group falls into three main project areas. In the first, we are investigating electronic effects in heterometallic compounds containing paramagnetic transition metals. We have discovered simple yet powerful synthetic methods that allow for systematic metal atom substitution and study of a well-defined series of heterometallic compounds to elucidate trends in structure and bonding. In the second project area, we are isolating and studying reactive intermediates that have metal-metal and metal-ligand multiple bonds in a linear M=M=L structure. Such intermediates are relevant to widely used catalytic transformations including cyclopropanation, aziridination, and C–H functionalization, but have not been subjected to rigorous study. In a third research area that is beginning to develop we are exploring the possibility that a new oxidation state of sulfur and its heavier congeners, namely the S23– or ‘subsulfide’ level, can be stabilized in transition metal complexes. Establishing this new intermediate oxidation state puts forth a new paradigm for how chalcogen-chalcogen bonds are made and broken, processes that are very important in biological, geological, and synthetic chemical systems. The themes that bind our research projects together are:
1. Explaining Bonding Phenomena that are Novel, Ambiguous, or Poorly Understood. Projects begin in my lab when we identify systems that present fundamental problems in chemical bonding. By elucidation of electronic structure, we seek to gain insights that help us to explain unusual physical or chemical properties of these systems.
2. Relating Electronic Structure to Reactivity. We study systems in which we hypothesize that chemical reactivity can be understood in the context of electronic structure. Establishing interrelations between electronic structure and reactivity is important to us because it allows predictions to be made about new reactions.
3. Correlating Experimental Measurements with Computational Results. Modern computational methods provide significant insights into electronic structure, but computations must be validated and tested by their ability to predict key experimental observables. A strong synergy between experiment and computation is indispensable to our research.