N 2 cleavage by silylene and formation of H 2 Si(μ-N) 2 SiH 2 .

Fixation and functionalisation of N 2 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 2 ) matrix by the reaction of hydrogen and laser-ablated silicon atoms. The four-membered heterocycle H 2 Si(μ-N) 2 SiH 2 , the H 2 SiNN(H 2 ) and HNSiNH complexes are characterized by infrared spectroscopy in conjunction with quantum-chemical calculations. The synergistic interaction of the two SiH 2 moieties with N 2 results in the formation of final product H 2 Si(μ-N) 2 SiH 2 , 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 2 , leading to cleave the non-polar and strong NN triple bond.