Comparison of methods to estimate geometric and electronic properties on sulfur containing compounds
A theoretical and experimental analysis of the geometric and electronic properties of compounds containing the aminosulphonylamino moiety was carried out. The theoretical properties were calculated using molecular orbital ab initio methods at the Hartree-Fock (HF) and second order Möller-Plesset (MP2) levels of theory, local density functional (LDF) ab initio methods and the semi-ab initio method, SAM1, on sulphamide and seven heterocyclic compounds containing the aminosulphonylamino group. The experimental analysis has been performed using x-ray structures of related compounds gathered in the Cambridge Structural Database together with experimental dipole moments and 13CNMR shifts of some of the compounds studied. Comparison of the experimental analysis with the theoretical results indicates that none of the methods studied is the most adequate to describe the geometry and electronic distribution of these molecules. The use of the 6-31G* basis set to compute the geometry of these molecules and methods which include electronic correlation (MP2/61G*//RHF/6-31G*, MP2/6-31G* and LDF) to quantify their electronic distribution are proposed.