Aromaticity‐promoted CO2 Capture by P/N‐Based Frustrated Lewis Pairs: A Theoretical Study

Carbon dioxide (CO2, a common combustion pollutant) releasing continuously into the atmosphere is primarily responsible for the rising atmospheric temperature. Therefore, CO2 sequestration has been an indispensable area of research for the past several decades. On the other hand, the concept of aromaticity is often employed in designing chemical reactions and metal‐free frustrated Lewis pairs (FLPs) have proved ideal reagents to achieve CO2 reduction. However, considering FLP and aromaticity together is less developed in CO2 capture. Here we report theoretical investigations on the aromaticity‐promoted CO2 activation, involving heterocyclopentadiene‐bridged P/N‐FLPs. The calculations reveal that furan‐ and pyrrole‐bridged P/N‐FLPs can make CO2 capture both thermodynamically and kinetically favorable (with activation energies of 5.4–7.7 kcal mol−1) due to the aromatic stabilization of the transition states and products. Our findings could open an avenue to the design of novel FLPs for CO2 capture. Aromaticity‐enhanced CO2 capture is demonstrated via thorough DFT calculations on P/N‐based FLPs (amidophosphorane). Aromatic furan‐ or pyrrole‐bridged FLPs featured better performance on CO2 capture, which could be attributed to the gradual gain of aromaticity in the process of activation. On the contrary, aluminacyclopentadiene‐bridged FLP gains anti‐aromaticity in the transition state, leading to relative higher activation energies for CO2 capture.