Synthesis and Characterization of Pincer-Molybdenum Precatalysts for CO2 Hydrogenation

Synthesis and Characterization of Pincer-Molybdenum Precatalysts for CO2 Hydrogenation

Yuanyuan Zhang†‡, Paul G. Williard‡, and Wesley H. Bernskoetter*†‡
† Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
‡ Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
Organometallics, Article ASAP
DOI: 10.1021/acs.organomet.5b00955
Publication Date (Web): January 19, 2016








A family of low-valent molybdenum complexes supported by the pincer ligand PNMeP (PNMeP = MeN(CH2CH2PPh2)2) was prepared and characterized, including (PNMeP)Mo(C2H4)2, which contains an agostic interaction between the metal and the N-methyl substituent. This β-agostic C–H bond was cleaved by molybdenum and produced a cyclometalated molybdenum formate complex, (κ4-PNMeP)Mo(C2H4)(κ2-O2CH), upon exposure to CO2. This species serves as a promotor of CO2 hydrogenation to formate under basic conditions, a rare transformation for group VI metals. The performance of the precatalyst was enhanced with the addition of Lewis acid salts.