Quantum-chemical study of the torsional potential function of thiophenol molecule

Single-determinant Hartree-Fock treatment with the 6-31G(d), 6-31G(dp), 6-3 1++G(dp), DZV, 6-311G(dp), and TZV basis sets, as well as allowance for cor relation energy in terms of the Moller-Plesset second-order perturbation th eory and DFT computational schemes (Becke 3LYP hybrid functional) to estima te C(sp)2-S torsional potential functions for thiophenol. The MP2(fc)/6-31G (d), MP2(fc)/6-31G(dp), and Becke 3LYP/6-311G(dp) results suggest free rota tion about the C(sp)2-S bond. Interaction of lone electron pairs of sulfur and the ring pi system in different conformations was considered using the natural bond orbital procedure.