Di(carbene)-Supported Nickel Systems for CO₂ Reduction Under Ambient Conditions

Di­(carbene)-supported nickel species 1 and 2 are efficient catalysts for the room-temperature reduction of CO2 to methanol in the presence of sodium borohydride. The catalysts feature unusual stability, particularly for a base metal catalyst, enabling >1.1 million turnovers of CO2. Moreover, while other systems involve more expensive reducing reagents, sodium borohydride is inexpensive and easily handled. Furthermore, effecting reduction in the presence of water enables direct access to methanol. Preliminary mechanistic data collected are most consistent with a mononuclear nickel active species that mediates rate-determining reduction of a boron formate.