Solvent effects on the chemical shifts of halogenated derivatives of diphenyl sulphone, dibenzothiophene and dibenzothiophene 5,5-dioxide

Abstract

The ¹H NMR spectra of the title compounds were recorded in [²H₆]DMSO and CDCl₃ solvents and analysed using the LAOCOON-3 program. A different degree of shielding of the two protons ortho to the halogen atoms was observed in the tricyclic compounds. The sign and the magnitude of this differential shielding depends on both the halogen substituent and the solvent. Models for the solute–solvent interactions are suggested, and it is proposed that both mesomeric and steric effects contribute to the observed NMR results.