Cleavage of the N≡N Triple Bond and Unpredicted Formation of the Cyclic 1,3‐Diaza‐2,4‐Diborete (FB)(2)N(2) from N(2) and Fluoroborylene BF

A complete cleavage of the triple bond of N(2) by fluoroborylene (:BF) was achieved in a low‐temperature N(2) matrix by the formation of the four‐membered heterocycle FB(μ‐N)(2)BF, which lacks a trans‐annular N−N bond. Additionally, the linear complex FB=N−N=BF and cyclic FB(η (2)‐N(2)) were formed. These novel species were characterized by their matrix infrared spectra and quantum‐chemical calculations. The puckered four‐membered‐ring B(2)N(2) complex shows a delocalized aromatic two‐electron π‐system in conjugation with the exo‐cyclic fluorine π lone pairs. This work may contribute to a rational design of catalysts based on borylene for artificial dinitrogen activation.