105 Kinetics of H2 and Co2 Addition to a Ru Hydorgenation Catalyst That Converts Co2 to Formate

Faculty Mentor: Caroline T. Saouma (Chemistry, University of Utah)

The hydrogenation of CO₂ to formate is generally thought to proceed via CO₂ insertion into a metal hydride. Indeed, (PNP)Ru(H)₂(CO) readily inserts CO₂ to give the corresponding (PNP)Ru(H)(CO)(OCHO) species (PNP = 2,6-bis(di-tert butylphosphinomethyl)pyridine). However, we have observed that the formate species can also be formed from addition of H₂ to the ligand-bound CO₂ species, (CO2-PNP)Ru(H)(CO). Given that ligand-bound CO₂ species are generally regarded as detrimental to catalysis, we sought to determine the mechanism of formate production. Ongoing kinetic studies on H₂ and CO₂ addition to the pertinent Ru metal species are being utilized to deduce the exact catalytic mechanism that are relevant for H₂ addition to carbonyl substrates.