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