Electronic structures and conformational stabilities of some organo-sulfur compounds

Abstract

Ab initio calculations were carried out for some organo-sulfur molecules using STO—3G and 4—31G bases, and a general basis which includes d-orbitals (D) in the sulfur atom. In order to make a comparison between the results of ab initio and semi-empirical procedures, the calculations were also carried out by the CNDO/2 ( spd′) procedure. The exponent ζ value of the d-orbitals for the sulfur atom was optimized using the molecule HSCH 2SH. From these calculations very useful information was obtained about the rotational isomerism of these molecules. The 4—31G and D bases reproduced the experimental conformational stability of molecules with two sulfur atoms, but the STG—3G basis was unsuitable.