Experimental and theoretical studies of the charge-density distribution in 3,3,6,6-tetramethyl-S-tetrathiane

Abstract

A multipole model of the charge-density distribution in a ring containing C—S and S—S bonds has been obtained using high-resolution X-ray diffraction data from a single crystal of 3,3,6,6-tetramethyl-S-tetrathiane. Analysis of the bond critical points in both experimental and ab initio densities suggests a sulfur–sulfur bond order only slightly greater than unity. For isolated molecules, ab initio geometry optimisations predict a small energy stabilisation of the chair conformer relative to the twist-boat conformer observed in the crystalline state.