Formate-Catalyzed\nSelective Reduction of Carbon Dioxide\nto Formate Products Using Hydrosilanes

Abstract

Formate\nsalts were found to be active and selective homogeneous\ncatalysts for the hydrosilylation of CO₂. Counter cations\nand solvents strongly affected their catalytic activity. The use of\ntoluene as a solvent rendered the recyclable catalyst system. Lewis\nbasic polar solvents such as <i>N</i>-methylpyrrolidone\nand dimethyl sulfoxide significantly accelerated the reaction. The\nturnover number approached up to 1800. Analyses of the Fourier-transform\ninfrared spectroscopy and in situ ¹H nuclear magnetic resonance\nspectra suggested that the catalysis proceeds via electron donation\nfrom the solvent to hydrosilane, thereby accelerating the hydride\ntransfer step.