Nonspectator Phosphorus Ligands for Catalysis

With the support of the Chemical Catalysis and the Chemical Structure, Dynamics, and Mechanism B Programs in the Division of Chemistry, Alexander Radosevich of the Department of Chemistry at Massachusetts Institute of Technology is studying the development of new metal-phosphorus complexes as homogeneous catalysts for small molecule conversion chemistry. Catalysis plays a central role in the scalable, economical, and sustainable synthesis of chemicals, including fuels, drugs, and materials. In this project, Dr. Radosevich and his students are creating new metal-based catalysts that bear phosphorus-containing substituents that react in new ways. The specific reactions to be pursued in this research include schemes to convert alkenes and alcohols to value-added products. Graduate and undergraduate researchers working with Dr. Radosevich will receive training in a broad set of spectroscopic, physical, and synthetic chemistry techniques. Achieving these training objectives will contribute to a vital workforce that underpins the economic competitiveness of US-based chemical industries. Dr. Radosevich and his research group participate in a number of outreach efforts advancing the goal of broad participation in science. Dr. Radosevich’s laboratory is also host to visiting international researchers at all levels of experience, contributing to ongoing US leadership in international scientific engagement. Alexander Radosevich and his research team are pursuing the experimental physical, thermodynamic, and mechanistic foundation for the development of new nonspectator ligands based on tricoordinate phosphorus. This work centers on the proposition that enforcing nontrigonal geometries on tricoordinate phosphorus ligands will yield the structural and electronic conditions necessary to access higher-coordinate phosphorus ligands. The specific objectives being pursued comprise experiments that: (1) infer HOMO-LUMO electronic structure of nontrigonal tricoordinate phosphorus ligand complexes through analysis of 31P NMR chemical shift anisotropy, (2) develop nonspectator tricoordinate phosphorus ligands for catalyzed conversions of alkenes involving hydrido- and hydrocarbyl- metallophosphoranes, and (3) develop nonspectator tricoordinate phosphorus ligand complexes as catalysts for alcohol conversion chemistry involving alkoxy metallophosphoranes. These studies are providing a detailed, experimental quantification of the impact of nontrigonal distortion on electronic structure in tricoordinate phosphorus-containing complexes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.