Electride-Sponsored Radical-Controlled CO2 Reduction to Organic Acids: A Computational Design.

Converting CO2 into high-value chemicals has been regarded as an important solution for a sustainable low-carbon economy. In this work, we have theoretically designed an innovative strategy for the absorption and activation of CO2 by the electride N3Li, that is, 1,3,5(2,6)-tripyridinacyclohexaphane (N3) intercalated by lithium. DFT computations showed that the interaction of CO2 with N3Li leads to the catalytic complex N3Li(eta(2)-O2C), which can initiate the radical-controlled reduction of another CO2 to form organic acids through radical reactions in the gas phase. The CO2 reduction consists of four steps: (1) The formation of N3Li(eta(2)-O2C) through the combination of N3Li and CO2, (2) hydrogen abstraction from RH (R=H, CH3, and C2H5) by N3Li(eta(2)-O2C) to form the radical R. and N3Li(eta(2)-O2C)H, (3) the combination of CO2 and the radical R. to form RCOO., and (4) intermolecular hydrogen transfer from the intermediate N3Li(eta(2)-O2C)H to RCOO.. In the whole reaction process, the CO2 moiety in the complex N3Li(eta(2)-O2C) maintains a certain radical character at the carbon atom of CO2 and plays a self-catalyzing role. This work represents the first example of electride-sponsored radical-controlled CO2 reduction, and thus provides an alternative strategy for CO2 conversion.