Electron spin resonance studies. Part XLVII. Sulphinyl- and sulphonyl-substituted aliphatic radicals

Abstract

E.s.r. spectroscopy has been employed to characterise sulphinyl-[·CR¹R²S (O) R³] and sulphonyl-conjugated [·CR¹R²S(O₂)R³] carbon radicals. The former group are generated during the reaction between 1,3-bis-sulphoxides and the hydroxyl radical and from sulphoxides with the phenyl radical; the latter are formed from sulphones with either phenyl or hydroxyl (the reactivities and selectivities of which are compared). There is evidence that both groups of radicals are coplanar at the tervalent carbon atom, and that the sulphinyl group withdraws ca. 6% of the spin from that carbon atom, and that the sulphonyl group has no capacity for spin-delocalisation. Evidence is also presneted that acyclic radicals which posses a β-sulphinyl or β-sulphonyl substituent readily fragment to the corresponding alkene and a radical RSO· or RSO₂·.