A non-empirical molecular orbital study of valence tautomers of C2H3N

The valence tautomers of C₂H₃N have been examined by non-empirical molecular orbital calculations using two split-valence shell basis sets. All geometries were fully optimized using the 4–31G basis set and these structures were then used in 6–31G basis set calculations. The order of stability of the three possible cyclic isomers is 1-azirine > cyclic carbene > 2-azirine. The profiles for conversion of vinylmethylene into cyclopropene, vinylnitrene into 1-arizine, and iminomethylene into 2-azirine have all been shown to have barriers.