SusChEM: Magnesium-catalyzed hydrosilylation and hydroboration for efficient carbon-silicon and carbon-boron bond formation

Iowa State University, Ames IA

Investigators

Abstract

In this project funded by the Chemical Catalysis program of the Chemistry Division, Professor Aaron Sadow of Iowa State University is developing new catalytic reactions to construct complex systems. The products of these reactions are reagents commonly used as synthetic intermediates for materials and fine chemical technologies. Current processes to create important synthetic intermediates often generate significant quantities of waste or employ expensive metals. The catalysts being studied in this project are instead based on abundant magnesium, calcium or zinc compounds. This chemistry should yield catalytic processes with greater efficiency, reduced demand for precious metals, and diversified synthetic routes to important compounds. Professor Sadow is also studying the reaction mechanisms and the factors that control the chemistry of the catalytic reactions, which will help to optimize the outcomes of the catalysis and to add to fundamental knowledge of the chemistry. Additionally, outreach activities are being pursued to disseminate information on chemical sustainability to public audiences through university and public seminar series. Graduate and undergraduate students are receiving broad training in chemical synthesis, characterization, mechanistic study, and molecular design, which are important for success in any scientific problem-solving endeavor related to catalysis. Professor Sadow is studying the catalytic conversion of oxygen-containing organic molecules. Early transition-metal alkoxides do not readily transfer to weak electrophiles such as silanes due to limiting factors of the strong, polar metal-oxygen bonds in these compounds. The transfer of alkyl groups from main group metal compounds, such as Grignard reagents, is well established and useful in synthetic chemistry for silicon-carbon and boron-carbon bond formations. Instead, the limitations on magnesium-carbon bond formations hinder the application of facile alkyl group transfer reactions in catalytic transformations that employ main group metal catalysts. Professor Sadow is studying group transfer reactions centered on magnesium and calcium, along with related oxophilic metal centers. These studies are being accomplished through the development of early-metal catalytic sites and reagents to efficiently and selectively transform oxygenates as well as through kinetic studies of organoelement bond formations involving group transfer from oxophilic main group metal centers. The work involves the synthesis of main group metal complexes with ligand environments that labilize strong metal-element bonds and while stabilizing reactive intermediates.