DFT Based Simulations Study for Comparative Prediction of Reactivity and Stability of Thiadiazoles

Abstract

HOMO and LUMO energies and thermodynamics of a set of thiadiazoles have been evaluated based on Density Functional Theory (DFT) at B3LYP level of theory at 6-31G* in the Gaussian program. The results of HOMO density of frontier orbitals indicate that thiadiaoles, sequence of donor ability is in the order, 2-methyl-1,3,4-thiadiazole > 2,5-dimethyl-1,3,4-thiadiazole > 5-methyl-1,3,4-thiadiazol-2-amine > 1,3,4-thiadiazol-2-amine > 1,3,4-thiadiazole-2,5-diamine. The electron charge density allowed to find out different molecular properties such us the electrostatic potential and the dipole moment, which were finally subject to a comparison leading to a good match obtained between studied molecules. The intramolecular charge transfer has also been confirmed by an HOMO-LUMO analysis.