The molecular conformation of benzene sulphonyl chloride

Abstract

Recently Boggia et al. [ 21 recorded the microwave spectrum of this compound. From the a-type band spectrum they concluded that the molecule has a C, structure with the chlorine atom in the plane of the benzene ring (dihedral angle T = 0”). This is in evident contrast to the results of the electron diffraction investigation [ 11 in which it was possible to exclude this form while the experimental data could be approxi- mated equally well by either a model in which the benzene plane is perpen- dicular to the plane containing the sulphur-chlorine bond and the line bisecting the O=S=O angle (7 = 90”) or an asymmetric model with r = 75 + 5”. In the former of these two models the mean vibrational amplitudes associated with some of the rotation-dependent distances were considerably larger than in the latter model. It is the purpose of the present communication to show that the microwave spectroscopic data are not really in disagreement with the electron diffraction structure. From the electron diffraction bond lengths and bond angles the rotational constants