Hydrogenation of CO2 to Formate with H2 : Transition Metal Free Catalyst Based on a Lewis Pair.

Hydrogenation of CO2 to formate with H2 in the absence of transition metal is a long-standing challenge in catalysis. The reactions between tris(pentafluorophenyl)borane (BCF) and K2 CO3 (or KHCO3 ) are found to form a Lewis pair (K2 [(BCF)2 -CO3 ]) which can react with both H2 and CO2 to produce formate. Based on these stoichiometric reactions, the first catalytic hydrogenation process of CO2 to formate using transition metal free catalyst (BCF/M2 CO3 , M=Na, K, and Cs) is reported. The highest TON value of this catalytic process is up to 3941. Further research revealed the reaction mechanism in which the Lewis pair enables the splitting of H2 and the insertion of CO2 into the B-H bond.