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(η²-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(η²-O₂C) through the combination of N3Li and CO₂, (2) hydrogen abstraction from RH (R=H, CH₃, and C₂H₅) by N3Li(η²-O₂C) to form the radical R^. and N3Li(η²-O₂C)H, (3) the combination of CO₂ and the radical R^. to form RCOO^., and (4) intermolecular hydrogen transfer from the intermediate N3Li(η²-O₂C)H to RCOO^.. In the whole reaction process, the CO₂ moiety in the complex N3Li(η²-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.