A highly selective fluorescent chemosensor for turn-on recognition of Zn2+ and turn-off recognition of Cu2+ ions with applications in real samples, molecular logic gate and cell imaging studies

In this research work, we have successfully designed and developed a Schiff base fluorescent chemosensor for detecting Zn2+ and Cu2+ ions using absorption and fluorescence spectroscopy. A stable complex formation of L with Zn2+ was observed with a noticeable isosbestic point in the absorption spectra. Moreover, fluorescence “on-off” response with Zn2+ and Cu2+ was observed which indicates selectively senses of Zn2+ and Cu2+. This sensor displays 1:1 stoichiometric ratio with metal ions by 1H NMR titration, mass spectra, BH-plot and Job’s plot. Moreover, the recyclability of L was assessed through EDTA showing an efficient fluorescence “off-on-off” signal response. Furthermore, the (L+Zn2+) ensemble formed was used for selective recognize F− ion. L achieved an INHIBIT logic function using different chemical inputs and corresponding emission as output. The optimized structures of L and complexes (L+Zn2+ and L+Cu2+) were used to understand spectral properties using DFT which further calculated different reactivity descriptors. This selective sensitivity of L towards Zn2+ were successfully studied and used for detection of Zn2+ intracellularly in mouse breast adenocarcinoma cell.