Computational and photophysical probing interactions of newly synthesized benzothiazole azo-bonded molecules acting as potent antitubercular agents

Abstract

In the present work, we have presented a very detailed study of unprecedented mono-azo benzothiazole derivatives. The targeted molecules were synthesized by a single-step involving diazotizing the primary aromatic amines followed by resultant diazonium salts coupling with N, N-Diethyl-m-toluidine (DEMT) through electrophilic substitution reaction influenced by positive mesomeric effect (+M effect) under suitable experimental conditions. The FT-IR, UV–vis, Photoluminescence (PL), 1H NMR, 13C NMR, and HRMS techniques were used to investigate the synthesized mono-azo benzothiazole dye derivatives. Additionally, for the first time, calculations based on density functional theory have been used to examine the ground state geometry, electronic structure, and molecular characteristics potential region maps of four benzothiazole mono-azo architectures (CR1-CR4). The effectiveness of the synthesized dye colourants against M. tuberculosis, H37Rv was assessed by utilizing the agar well diffusion assay method (ATCC 27,294), amongst the studied mono-azo derivatives, CR3 and CR4 exhibited a good zone of inhibition compared to CR1 and CR2. The compound CR1 demonstrated sensitivity at 20 µM, compared to 48.2 µM for the reference gentamicin. The antibacterial activity of the CR1 and CR4 compounds was revealed to have a 19 mm zone of inhibition. The derivative CR1 displayed 42.86 and CR3 displayed 38.75 of the concentration IC50 in 100 μl/ml, respectively, based on their cytotoxic potentiality.