Experimental and theoretical study of electronic substituent effects in 4-aminoaryl (4-substituted aryl) sulphones

TLDR: In this paper, the electronic structure of 23 biologically active 4-aminoaryl (4-substituted aryl) sulphones were investigated by means of 1H nmr, 13C nmr and ir spectroscopy, as well as by semi-empirical all-valence CNDO/2 calculations, with and without sulphur d orbital participation Good linear intercorrelations were found among the spectral data and between these and computed electronic charges and the Hammett σp values.

Abstract: Substituent effects on the electronic structure of 23 biologically active 4-aminoaryl (4-substituted aryl) sulphones were investigated by means of 1H nmr, 13C nmr, and ir spectroscopy, as well as by semiempirical all-valence CNDO/2 calculations, with and without sulphur d orbital participation Good linear intercorrelations were found among the spectral data and between these and the computed electronic charges and the Hammett σp values On this basis the substituent effects are interpreted in terms of electronic charge perturbation, which is linearly transmitted from the substituent to the whole molecule, bridging SO2 group included The agreement between experimental and theoretical data is good and the trends do not depend on the inclusion or exclusion, in the calculations, of the sulphur d orbitals Strong and linearly related σ–π electron interactions operate between C-1 and C-1′ in the C(1)SO2C(1′) moiety; thus Koch and Moffitt's qualitative π-electron conjugation model for Case 2 type sulphones seems inadequate