Predicting Dinitrogen Activation by Carborane-Based Frustrated Lewis Pairs

Abstract

Activation of atmospherically abundant dinitrogen (N2) under mild conditions has been a great challenge in chemistry for decades because of the significantly strong NN triple bond. The traditional strategy of N2 activation was mainly limited to metallic species until the ground-breaking achievement of N2 activation by two-coordinated borylenes was achieved experimentally in 2018. On the other hand, carborane derivatives have attracted considerable interest for small-molecule activation. Still, the utilization of carborane derivatives in N2 activation remains elusive. Here, we design four types of carborane-based frustrated Lewis pairs (FLPs) to probe their potential for N2 activation by systematical density functional theory calculations. Interestingly, all these carborane-based FLPs are found to become favorable both kinetically and thermodynamically for activating N2 with low reaction barriers (ranging from 13.0 to 25.8 kcal mol–1) and high exothermicity, with ΔG values ranging from −37.5 to −51.0 kcal mol–1, indicating a high potential for metal-free N2 activation under mild conditions. Our study opens an avenue to metal-free N2 activation, highlighting the great importance of carborane derivatives in the field of N2 activation