Catalytic Hydrogenation of Carbon Dioxide with Ammonia-Borane by Pincer-Type Phosphorus Compounds: Theoretical Prediction.

Two theoretically designed and one experimentally reported pincer-type phosphorus compounds are found to be active for the hydrogenation of carbon dioxide with ammonia-borane. DFT, ONIOM(CCSD(T):MP2), and CCSD(T) computational results demonstrated that the reaction occurs through phosphorus-ligand cooperative catalysis, which provides an unprecedented protocol for metal-free CO2 conversion. The phosphorus compounds with the NNN ligand are more active than those with the ONO ligand. The planar conjugate ligand considerably improves the efficiency of the catalyst.