EXPLORING CO2 FUCTIONALIZATION WITH D6 COMPLEXES AND MATERIALS
Carbon dioxide (CO2), a potent greenhouse gas, is produced as a waste in many industrial processes, yet few processes incorporate CO2 as a C1 feedstock. To address this imbalance, we explore additional avenues for the use of CO2 to produce industrially relevant commodity chemicals via d6 transition metal complexes and materials. Acetic acid is commonly used as a solvent and reagent in industry. Coupling CO2 insertion with C–H activation of methane would allow the incorporation of two greenhouse gases into a single industrially relevant product. First, we developed a synthetic strategy to make (CCC)M–CH3 complexes where CCC = 1,3-bis(3-mesityl-3-benzo[d]imidazol-1-yl)benzene and M = Ir(III) and Rh(III). Second, we explore the direct insertion of CO2 into the Ir–CH3 complex for formation of acetates. With the aid of a Lewis acid, our (CCC)Ir–CH3 compound can perform CO2 insertion to yield (CCC)Ir–OAc.Ethanol is commonly used as a fuel additive, but there are advantages to utilizing butanol as a drop-in substitution for ethanol. We investigated this downstream transformation of ethanol upgrading to butanol. In these systems, the reactant ethanol would be derived from CO2 functionalization, enabling a more carbon neutral approach to the fuel industry. Ethanol upgrading was achieved with a mixed heterogeneous-homogenous poly(triazine)imide-(Cp*)Ir material under rigorous neat conditions. However, a homogeneous (Cp*)Ir system produced butanol under more mild aqueous conditions in a more promising development for realization of a cascade system for CO2 to butanol.