Dinitrogen Activation by Dihydrogen and Quaternary Cluster Anions AuNbBO^–: Nb- and B‑Mediated N₂ Activation and Au-Assisted Nitrogen Transfer

Nitrogen fixation and hydrogenation are important issues in chemistry and industry. Herein, we used mass spectrometry and quantum chemical calculations to identify the quaternary AuNbBO^– anions that can efficiently activate N₂ and H₂ to form imido (or amido) units in the products AuNbBON₂H₂^– under thermal collision conditions. In these reactions, Nb and B atoms work in synergy to dissociate N₂ and the Au atom acts as a reducing agent, which facilitates the removal of one activated N atom for the following hydrogenation process; generation of three-centered, two-electron bonds facilitates N₂ activation and N transformation. This study shows that the noble metal-assisted early transition metal boronyl cluster is highly reactive to facilitate thermal N–N and H–H bond cleavage, and NH (or NH₂) and NBO units, which are important intermediates in N₂ hydrogenation reactions, are formed. These findings may provide insight into the design of new catalysts for the synthesis of NH₃ from N₂ and H₂.