Predicting Dinitrogen Activation by Carborane-Based Frustrated Lewis Pairs

Activation of atmospherically abundant
dinitrogen (N2) under mild conditions has been a great
challenge in chemistry for
decades because of the significantly strong NN 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.