Ultraviolet photoelectron and ab initio study of the conformation of some p-Substituted α-Phenylthioacetonitriles

Abstract

The analysis of the He¹ photoelectron spectra of some p-substituted α-phenylthioacetonitriles (X-C₆H₄SCH₂CN; X = NO₂, Cl, H, CH₃, OCH₃,NH₂) shows evidence, in agreement with ab initio calculations, regarding the preferred conformation around the CC(ring)–S–C dihedral angle, ψ. By preference, ψ assumes large values; that is, the S–CH₂CN bond is significantly out of the ring plane. When the electron-releasing capability of X decreases, conformers with smaller ψ values have new features in the spectra. The dependence of the conformer distribution on steric and electronic factors is discussed.