The reactions of the ammoniumyl radical-cation (NH3+·) with sulphides and sulphoxides: an electron spin resonance investigation

Abstract

The results are described of an e.s.r. study of the reactions of NH₃⁺˙, generated from the Ti^III–NH₂OH couple, with a variety of sulphides and sulphoxides. Signals detected from sulphides include those from dimer radical-cations (R₂SSR₂⁺˙), as well as those derived by hydrogen loss (e.g.˙CHMeSEt from Et₂S) and fragmentation [e.g.˙CH₂SCH₂CO₂H from (HO₂CCH₂)₂S]. Sulphoxides give rise to alkyl and alkanesulphonyl (RSO₂˙) radicals, the latter of which are evidently derived from sulphinic acids formed in situ. Reactions of NH₃⁺˙ with both types of substrate are interpreted in terms of the initial formation of radical adducts [RṠ– NH₃⁺, R₂Ṡ(O)NH₃⁺] which can then undergo a variety of reactions, including substitution and fragmentation.