Chemistry of sulphines. Part XXIV. Dipole moments of sulphines

Abstract

Dipole moments have been measured for p,p′-disubstituted diphenyl sulphines (I), fused aromatic sulphines (II), adamantanethione S-oxide, and dichloro sulphine in benzene at 25°. The group dipole moment of the CSO system is 3·84 D directed towards the sulphine oxygen at an angle of 20° with the C–S bond. The CSO function in the aromatic diphenyl sulphines (I) and in fluorene-9-thione S-oxide (IIa) has a positive mesomeric moment in contrast with the carbonyl group in the corresponding ketones. The mesomeric PhCSO moment was calculated as 0·28 D. The CSO group moment was used to calculate PhCCl and the C–CI group moment in the isomeric chloro phenyl sulphines (Va and b). The latter data were used to calculate ClCCl in dichloro sulphine (IV). Vector addition of group moments in the fused xanthione S-oxide (IIb) reveals that zwitterionic structures play an important role. These structures are not encountered in the folded thioxanthione S-oxide (IIc). The configuration of the sulphoxide-sulphine (IId) was determined as anti by means of vector addition of group moments.