Efficient Conversion of Carbon Dioxide with Si-Based Reducing Agents Catalyzed by Metal Complexes and Salts.

Abstract

Homogeneous metal complex and salt catalysts were developed for the reductive transformation of CO2 with Si-based reducing agents. Cu-bisphosphine complexes were found to be excellent catalysts for the hydrosilylation of CO2 with polymethylhydrosiloxane (PMHS). The Cu complexes also showed high catalytic activity and a wide substrate scope for formamide synthesis from amines, CO2 , and PMHS. Simple fluoride salts such as tetrabutylammonium fluoride acted as good catalysts for the reductive conversion of CO2 to formic acid in the presence of hydrosilane, disilane, and metallic Si. Based on the kinetics, isotopic experiments, and in-situ NMR measurements, the reaction mechanism for both catalyst systems, the Cu complex and the fluoride salt, have been proposed.