Predicting σ⁰π² Carbene-Mediated Hydroboration and Bis-carbene Functionalization of Dinitrogen

Although the carbene-catalyzed N₂ fixation process had been investigated by scientists for decades prior to borylene species, the interest in the carbene-mediated N₂ activation process has drawn less attention than that of borylene species in the past few years, especially unique σ⁰π² carbenes. Herein, we demonstrate the important role of unique σ⁰π² carbenes in the 1,1-hydroboration and bis-carbene functionalization of N₂ using density functional theory calculations. Both being kinetically and thermodynamically favorable, the reaction barriers are as low as 13.7 and 16.6 kcal/mol, respectively. Additionally, such a σ⁰π² carbene can also achieve a series of X-H insertion reactions (X = H, CH₃, Bpin, or SiH₂Ph), with activation energies ranging from 8.2 to 15.3 kcal/mol. Our findings highlight a strong potential of carbenes with σ⁰π² electronic configuration in N₂ activation and its versatile transformations, providing valuable insights into main-group-element-mediated N₂ activation chemistry.