Cooperative Dinuclear Activation of a Formate Intermediate in the Hydrogenation of CO2 to Methanol.

CO2 hydrogenation to methanol is achieved by homogeneous catalysts through a formic acid derivative. Previous studies have focused on using large amounts of additives to activate this intermediate, such as strong acids, amines and alcohols. Hydrogenation of CO2 under basic conditions has been reported to only produce highly stable formate salts. We present in this contribution a novel method for formate activation that allows for CO2 hydrogenation to methanol under basic conditions, by bimetallic activation of the formate salt by a cobalt and a nickel complex. From various catalytic and stoichiometric experiments, we propose that the nickel catalyst binds the in situ-generated formate to activate it for intramolecular cobalt hydride transfer, leading to an intermediate that can be further hydrogenated to methanol. This strategy could open new avenues in CO2 hydrogenation under basic conditions, with implications for both homogeneously and heterogeneously catalyzed processes.