Protonation of alkyl aryl sulphides in antimony pentafluoride–fluorosulphonic acid solution

Abstract

The mode of protonation of several mono- and di-alkyl-substituted alkyl aryl sulphides in SbF₅–FSO₃H solution was studied by low temperature n.m.r. spectroscopy. Protonation on sulphur was observed for all substrates, as revealed by ¹H and ¹³C n.m.r. measurements. The measured chemical shifts of carbon atoms at various positions in the ions were compared with charge densities evaluated by the MINDO/3 procedure.