Solvent-controlled CO2 reduction by a Triphos-iron hydride complex

The selective reduction of CO2 is of high interest toward future applications as a C1-building block. Therefore, metal complexes that allow for the formation of specific CO2 reduction products under distinct reaction conditions are necessary. A detailed understanding of the CO2 reduction pathways on a molecular level is, however, required to help in designing catalytic platforms for efficient CO2 conversion with specific product formation. Reported herein is a unique example of a solvent-controlled reduction of CO2 using a Triphos-based iron hydride complex. In THF, CO2 reduction selectively leads to CO formation, whereas experiments in acetonitrile exclusively afford formate, HCOO-. In order to explain the experimental findings, theoretical calculations of the reaction pathways were performed and further demonstrate the importance of the applied solvent for a selective reduction of CO2.