Structure and conformation of chlorosulfonylisocyanate and cyclopropylisocyanate

Abstract

Ab initio molecular orbital calculations were carried out to determine the structure and conformation of chlorosulfonylisocyanate and cyclopropylisocyanate. Geometrical parameters and harmonic vibrational wavenumbers calculated at the MP2/6-31G(d,p) level showed that while chlorosulfonylisocyanate has only a gauche equilibrium structure, cyclopropylisocyanate exhibits two stable conformations. The rotational barriers are rather small. These theoretical results contribute to a clarification of available experimental results. Rotational constants and vibrational wavenumbers have also been analysed.