Hydrogenation of carbon dioxide to formate using ruthenium bis(diphosphino) complexes: Investigation of ligands containing proton relays

Electrochemical and thermal catalysts for the conversion of CO ₂ to CO, formate or formic acid are being developed with the goal of more efficient utilization of CO ₂ to produce useful fuels. Ongoing research in our group is focused on understanding secondary coordination sphere effects in catalysis. Incorporation of proton relays (nitrogen based functionality) into the backbones of phopshine ligands has been shown to assist catalysis by assisting multi-proton and multi-electron processes. Previous efforts in the utilization of proton relays for hydrogen activation are being applied to Ru complexes bearing PNP or P ₂N ₂ ligand motifs. The synthesis and catalytic activity of these new complexes will be presented with direct comparison of ligands with and without proton relays.