Deceptive simplicity in ABMX N.M.R. spectra. II. Assignment and inter-ring coupling in dibenzothiophen and its S-oxides

Abstract

The assignment of the chemical shifts of dibenzothiophen is presented as well as an analysis of the spectra of the sulphoxide and sulphone. A small inter-ring coupling exists in these compounds and also in dibenzoselenophen. The solvent dependence of the chemical shifts of dibenzothiophen has been briefly investigated but cannot be explained in simple terms.