Crystallographic study and molecular orbital calculations of thiadiazole derivatives. 1. Phenanthro[9,10- c]-1,2,5-thiadiazole 1,1-dioxide and acenaphtho[1,2- c]-1,2,5-thiadiazole 1,1-dioxide

Abstract

Single-crystal X-ray diffraction studies are reported for phenanthro[9,10- c]-1,2,5-thiadiazole 1,1-dioxide (I) and acenaphtho[1,2- c]-1,2,5-thiadiazole 1,1-dioxide (II). Ab initio molecular orbital (MO) calculations on the electronic structure, conformation and reactivity of I and II are also reported and compared with the X-ray results. A charge sensitivity analysis of the studied molecules has been performed by resorting to density functional theory (DFT), obtaining several sensitivity coefficients 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 moments and the total electron density maps, several conclusions have been inferred about the preferred sites of chemical reaction of the studied compounds.