Vibrational Spectra of Sulphonyl Derivatives. V. A Reassignment of the SO₂ Stretching Frequencies in Sulphonyl Fluorides

Abstract

The symmetric SO₂ stretching frequency in methane sulphonyl fluoride and a number of aromatic sulphonyl fluorides is reassigned to a frequency of 1210 cm^-1 on the basis of new infra-red evidence (vapour and solution spectra of CH₃SO₂F and the infra-red spectra of a number of aromatic sulphonyl chlorides and the corresponding fluorides). Complete vibrational assignments for benzene sulphonyl chloride, benzene sulphonyl fluoride, and methyl benzene sulphonate are also given. The S-F stretching frequency appears as a strong infra-red band near 780 cm^-1 and the aromatic sulphonyl frequency near 1090 cm^-1 is identified as being more specifically characteristic of the C_ar-S bond.