Effect of Intramolecular Hydrogen Bonding Interaction of Azo‐Hydrazone Tautomers of 3‐Diethylamino Phenol Based Azo Bonded Molecules and their Biological Potentialities

Abstract The synthesis of novel mono‐azo benzothiazole derivatives using 3‐Diethylaminophenol (3‐DEAP) as a common coupling component is an electrophilic substitution reaction that was influenced by the positive mesomeric effect (+M effect) under appropriate experimental conditions. Various spectroscopic and analytical methods, including UV‐vis, fluorescence, FT‐IR, ( 1 H and 13 C) NMR, and HRMS, were used to confirm the structural characteristics of the synthesized molecules. Further, the Gaussian 09, CAM‐B3LYP/LANL2MB functions are used to predict the quantum chemical characteristics and their molecular electrostatic potential region of all the designed mono‐azo derivatives. Based on the investigations of UV‐Vis, interactions between intramolecular hydrogen bonds were observed in a variety of solvents and polarities, with a maximum in the 508–534 nm range. The gram‐positive and two gram‐negative bacterial strains were utilized for antibacterial activity in order to examine the biological effectiveness of the colourants. The coupling component with benzothiazole derivative showed a 14 mm zone of inhibition against the Gram‐negative bacteria Salmonella typhi . When compared to the standard BHT and EDTA as the positive control, the data from the DPPH and FIC assay technique of the titled compounds showed that all colourants have promising anti‐oxidant capabilities.