A structural study on the azide–tetrazole equilibrium in the azidobenzothiazole system. DFT-treatment

Abstract

Many 2-substituted benzothiazole derivatives are reported to possess a broad spectrum of biological activities, 2-azidobenzothiazole is scarely reported in the literature. This study investigates the structural properties of some azidobenzothiazoles, in addition to the azido–tetrazole isomerism. All calculations were carried out using a Gaussian 09 package and the DFT-B3LYP/6-311+G(d,p) procedure.The optimized geometry, the NBO-charge density, and the molecular orbitals, of all the studied species were investigated and discussed. The azide–tetrazole isomerism proved to be initiated by a “π-atomic orbital” overlap process rather than by an “electrostatic” attraction process. Solvent effect on the studied isomerism for the parent 2-azidobenzothiazole has been investigated. The Self Consistent Reaction Field (SCRF) theory and the Polarizable Continuum Model (PCM) at the B3LYP/6-311+G(d,p) level were used.