Radical anions and cations derived from enedithiols, hydroxy-enethiols, and saturated dithiols

Abstract

<p>In the bicyclo2.2.1heptane system, the following radical ions were prepared: semidithione, monothiosemidione, dithiete radical cation, and dithiin radical cation. All exhibited a large hyperfine splitting by hydrogen in the 7-anti position. The large splitting was expected in all cases due to the symmetry of the HOMO of each spin-label with respect to a plane bisecting the C(,2)-C(,3) bond in the bicyclic system. The differences in values of splitting constants in the various radical ions could be related to differences in spin density at carbons 2 and 3;Monothiosemidiones, dithiete radical cations, and dithiin radical cations were also prepared in the cyclohexane and butane systems. The differences in spin density at C(,2) and C(,3) in these systems were the same as those noted for the bicyclic radical ions;Bicyclo2.2.1heptane-2,3-dithiol, 2,3-butanedithiol, and 1,2-propanedithiol produced dithiete radial cations in sulfuric acid, while 1,2-ethanedithiol and 1,3-propanedithiol gave cyclic disulfide radical cations. Benzyl disulfide radical cation was obtained from benzyl mercaptan. The splitting constants for the disulfide radical cations and several other sulfur-containing radical cations did not fit the a('H) (PROPORTIONAL) (rho) relationship observed for hfsc of hydrogens (alpha) to a carbon atom containing an unpaired electron. For the disulfides, the inconsistency was believed to be due in part to changes in hybridization of the orbital on sulfur occupied by the unpaired electron.</p>