Conjugation effects. 12. Electronic structure of alkyl phenyl sulfides, sulfoxides, and sulfones

Abstract

1. The p,π conjugation of unshared electron pairs of the heteroatom with the π system of the benzene ring has a determining influence on the distribution of the ir-charge density in alkyl phenyl sulfides. Acceptor IR interaction of the S atom with the unsaturated fragment plays a significant role only in some alkyl phenyl sulfoxides and sulfones. 2. Increasing branching of the alkyl substituent in the order Me, Et, i-Pr, and t-Bu leads in the alkyl phenyl sulfides to a change in the steric interactions alkyl-benzene ring, as well as to a deterioration of thep,π conjugation of the S atom with the aromatic fragment, due to disturbance of the coplanarity of the molecules. In the alkyl phenyl sulfoxides and sulfones the induction and resonance interaction of the SOR and S02R groups with the ring remains practically unaffected.