Electronic Structure of Sulfanenitriles

Ab initio calculations have been carried out to analyze the electronic structure of organosulfur compounds with S≡N. The electronic structures of R3S≡N, R(O)S≡N, and RS≡N have been compared. The calculations suggest that the S–N interactions should be taken as a hybrid of the S≡N triple bond and the S+–N− single bond. The balance between the two resonating structures shift towards a S≡N triple-bonded arrangement with an increase in the electronegativity of substituents on sulfur. The strength of the Lewis basicity of sulfanenitriles has been estimated by studying their proton affinities and the complexation energies with BH3. On the potential energy surface of H3S≡N, this hypervalent compound has been shown to be a high-energy local minimum; although its 1,2-H shift isomers are all more stable, the barrier for the 1,2-shift is very high.