THF-Assisted CO₂ Reduction Catalyzed by Electride Mg₂EP: Insight from DFT Calculations

Hydroboration and hydrogenation reductions of CO₂ catalyzed by a porphyrinoid-based dimagnesium(I) electride (Mg₂EP) were investigated by density functional theory calculations. Herein, the presence of potentially excess electrons located at the Mg-Mg bond endows Mg₂EP with the ability to activate small molecules such as CO₂, HBpin, and H₂, thus opening up the possibility for further CO₂ conversion. The Mg₂EP-catalyzed hydroboration of CO₂ to HCOOBpin is predicted to have relatively higher activity in comparison to the hydrogenation reduction to formic acid (HCOOH). Interestingly, the common solvent molecule tetrahydrofuran as an auxiliary can coordinate with the Mg center to effectively weaken the bonding interaction between the dimagnesium center and the intermediate species from the CO₂ conversion, thereby promoting the catalytic cycle for the CO₂ hydroboration. The present results suggest that the electride Mg₂EP is promising for the molecular catalyst in the CO₂ transformation.