Schiff base of 4E,10E-4-(2-(4-nitrophenyl)-N-((1H-indol-3-yl)methylene) benzenamine-based “turn-on” fluorescence chemosensor for highly selective detection of Ni2+, Fe3+, and Mg2+ ions

Abstract

A Schiff base of 4E,10E-4-(2-(4-nitrophenyl)-N-((1H-indol-3-yl)methylene) benzenamine was synthesized and characterized by 1H&13C-NMR, FT-IR, and ESI–MS spectroscopy. UV–visible and fluorescence studies were explored for chemosensor ICPA to detect Ni2+, Fe3+, and Mg2+ by fluorescence chemosensor “turn-on” method in 10 mM HEPES buffer in EtOH/H2O (1:4, v/v) medium. Chemosensor ICPA binds with the selective heavy metal ions and could be proved in very low detection limits. Job’s plot demonstrates 1:1 stoichiometric complexes of ICPA + Ni2+, ICPA + Fe3+, and ICPA + Fe3+ with the calculated mole fraction of 0.5 μM. Binding constant values calculated using the Benesi–Hildebrand method are found to be 3.45 × 108 M−2, 5.63 × 104 M−2, and 8.63 × 103 M−2, respectively. Competitive metal ions tests were also carried out with transition metal ions. Furthermore, HeLa cell activity at different concentrations added with ligand to perform inhibition capability of the probe was also carried out.