N cleavage by silylene and formation of HSi(μ-N)SiH.

Fixation and functionalisation of N by main-group elements has remained scarce. Herein, we report a fixation and cleavage of the N ≡ N triple bond achieved in a dinitrogen (N) matrix by the reaction of hydrogen and laser-ablated silicon atoms. The four-membered heterocycle HSi(μ-N)SiH, the HSiNN(H) and HNSiNH complexes are characterized by infrared spectroscopy in conjunction with quantum-chemical calculations. The synergistic interaction of the two SiH moieties with N results in the formation of final product HSi(μ-N)SiH, and theoretical calculations reveal the donation of electron density of Si to π* antibonding orbitals and the removal of electron density from the π bonding orbitals of N, leading to cleave the non-polar and strong NN triple bond.