Computational study on the vinyl azide decomposition.

The decomposition mechanism of vinyl azide (CH2CHN3) has been studied by calculations of the electronic structure. In addition, a study based on the topology of the electron charge density distribution and its Laplacian function, within the Quantum Theory of Atoms in Molecules (QTAIM), has been carried out with the aim of comprehending the electron redistribution mechanisms that take place in the formation of vinyl nitrenes. The electronic structure calculations reveal that the decomposition of the s-cis conformer of vinyl azide leads to the formation of ketenimine through a single-step conversion, s-cis-CH2CHN3 → CH2CNH + N2, while the conversion of the s-trans conformer to acetonitrile occurs in two steps, s-trans-CH2CHN3 → cyc-CH2NCH + N2 → CH3CN + N2. The topological analysis of the L(r) function reveals that triplet vinyl nitrene has one lone pair on the valence shell charge concentration (VSCC) of nitrogen and thus could act as a monodentate Lewis base, while singlet vinyl nitrene has two lone pairs on the VSCC of nitrogen and thus could act as a bidentate Lewis base.