Collaborative Research: Hydrogen Atom Transfer Lewis Base Catalysis

University Of Texas At Arlington, Arlington TX

Investigators

Abstract

With funding from the Chemical Synthesis Program in the Chemistry Division, Junha Jeon at the Department of Chemistry at the University of Texas at Arlington and Gyu Leem at the Department of Chemistry of the SUNY College of Environmental Science and Forestry are developing new methods to use inexpensive and environmentally benign silicon-based reagents to produce high-value chemicals and materials. A number of chemical processes involve the transfer of both a hydrogen and an electron (the process is abbreviated HAT). This study utilizes silicon complexes in the presence of potassium to provide access to both hydrogen atom (hydrogen and one electron) and hydride (hydrogen and two electrons) transfer. If successful, these studies could provide low-cost, operationally simple, environmentally sustainable HAT and open up new avenues to the synthesis of key intermediates and useful polymeric materials. The broader impacts of this research include the recruitment and training of the next generation of scientists, with a particular emphasis on encouraging participation from women and underrepresented minority groups in the chemical sciences. This multi-disciplinary project involves Dr. Junha Jeon [synthetic silicon chemistry, University of Texas at Arlington] and Dr. Gyu Leem [polymer chemistry, SUNY College of Environmental Science and Forestry] as the primary investigators. In addition, there are two additional collaborations involving Drs. Jiali Gao [computational, University of Minnesota] and Brad Pierce [EPR spectroscopy, University of Alabama]. Through theoretical and experimental methods, the mechanistic origin of 'hydrogen-hydride transfer duality' associated with a potassiated hypercoordinate hydridosilicon species is determined. The of 'hydrogen-hydride transfer duality' refers to a mode of competing single or two-electron transfer reactions of hypercoordinative hydrosilicon systems and is termed alkali metal Lewis base-catalyzed complexation-induced hydrogen atom transfer. In addition to the mechanistic investigations, (1) enantioselective redox-neutral, branch-selective olefin hydrosilylation via LBCI-HAT and (2) the extension of the process to alkali metal-Lewis base-catalyzed, hydrogen atom transfer radical polymerization (HATRP) and chain extension of HATRP for the synthesis of of multiblock copolymers are developed. 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.