An electron spin resonance study of dialkylaminothiyl (R2NS·), dialkylaminosulphinyl (R2NSO), and alkyl(sulphinyl)aminyl [RNS(O)X] radicals. Radical addition to N-sulphinylamines

Abstract

Photochemically generated t-butoxyl (or trimethylsiloxyl) radicals react with bis(dialkylamino) sulphides or sulphoxides, containing primary N-alkyl groups, to produce dialkylaminothiyl (R₂NS·) or dialkylaminosulphinyl (R₂NSO) radicals, respectively. The e.s.r. spectra of these radicals have been detected and show a(N) 10.7 G, g 2.0155 (R₂NS·) and a(N)ca. 6.5 G, g 2.0060 (R₂NSO). t-Butoxyl, trimethylsiloxyl, methyl, and t-butyl radicals (X·) add rapidly to the sulphur atom of N-sulphinylalkylamines to produce alkyl(sulphinyl)aminyl radicals [RNS(O)X], which are detected by e.s.r. spectroscopy [a(N) 8.4–10.3 G, g ca. 2.0042]. The e.s.r. spectra are discussed in terms of the electronic structure and conformation of these radicals. The 1-hydroxy-1-methylethyl radical reduces N-sulphinyl-t-butylamine, probably to give the radical Bu^tNSOH rather than the tautomeric aminosulphinyl radical Bu^tN(H)SO.