A novel imidazole bearing bithiophene benzothiazole as a ratiometric fluorescent sensor for the selective discrimination of Al3+ions: Application to environmental water, pharmaceutical samples, and fluorescence live cell imaging

Owing to the extensive application of aluminium ions (Al3+) in numerous industrial platforms, it is vital to design a chemosensor for the selective detection of Al3+ ions. Hence, we have attempted to introduce new imidazole appended bithiophene benzothiazole-based fluorescent sensor 2-(5 '-(4,5-diphenyl-1H-imidazol-2-yl)-[2,2-bithiophen]-5-yl)benzo[d]thiazole (DIBT), for the fluorescence ratiometric recognition of Al3+ ions in an aqueous medium (acetonitrile/water 8:2 v/v). We employed Job's plot experiments to study the mode of complexation of the sensor DIBT with Al3+ ions. The ratio of binding stoichiometry of the DIBT thorn Al3+ complex was found to be 1:1. The mode of binding was further verified using the 1H NMR titration experiments and HRMS analysis. The detection limit of DIBT with Al3+ was found to be 13.7 nM. We performed DFT and TD-DFT cal-culations to get in-depth insights into the mechanical aspects. The chelation-enhanced fluorescence type sensor DIBT was analyzed for its practical application in real water and pharmaceutical samples. The sensor DIBT can effectively track Al3+ ions in live Escherichia coli (E-coli) bacterial cells.