Structural features of the carbon–sulfur chemical bond: a semi-experimental perspective

In this work, semi-experimental (SE) and theoretical equilibrium geometries of 10 sulfur-containing organic molecules, as well as 4 oxygenated ones, are determined by means of a computational protocol based on density functional theory. The results collected in the present paper further enhance our online database of accurate SE equilibrium molecular geometries, adding 13 new molecules containing up to 8 atoms, for 12 of which, to the best of our knowledge, the first SE equilibrium structure is reported. We focus in particular on sulfur-containing compounds, aiming both to provide new accurate data on some rather important chemical moieties, only marginally represented in the literature of the field, and to examine the structural features of carbon-sulfur bonds in the light of the previously presented linear regression approach. The structural changes issuing from substitution of oxygen by sulfur are discussed to get deeper insights on how modifications in electronic structure and nuclear potential can affect equilibrium geometries. With respect to our previous work, we perform nonlinear constrained optimizations of equilibrium SE structures, using a new general and user-friendly software under development in our group with updated definitions of useful statistical indicators.