Crystallographic study and molecular orbital calculations of thiadiazole derivatives. 2. 3,4-diphenyl-1,2,5-thiadiazole 1-monoxide

E. E. CASTELLANO; O. E. PIRO; J. A. CARAM; M. V. MIRIFICO; S. L. AIMONE; E. J. VASINI; A. MARQUEZ-LUCERO; D. GLOSSMAN-MITNIK

Journal Molecular Structure

Elsevier

Año: 2002 vol. 604 p. 195 - 203

Abstract  Single-crystal X-ray diffraction studies are reported for 3,4-diphenyl-1,2,5-thiadiazoline 1,1-dioxide (I), 3,4-diphenyl-1,2,5-thiadiazolidine 1,1-dioxide(II) and 4-ethoxy-5-methyl-3,4-diphenyl-1,2,5-thiadiazoline 1,1-dioxide (III). Ab initio MO calculations on the electronic structure, conformation and reactivity of these compounds are also reported and compared with the X-ray results. A charge sensitivity analysis is performed on the results applying concepts derived from density functional theory, obtaining several sensitivity coef®cients such as the molecular energy, net atomic charges, global and local hardness, global and local softness and Fukui functions. With these results and the analysis of the dipole moment and the total electron density and electrostatic potential maps, several conclusions have been inferred about the preferred sites of chemical reaction of the studied compounds.