Experimental and Theoretical Studies on a Simple S–S-Bridged Dimeric Schiff Base: Selective Chromo-Fluorogenic Chemosensor for Nanomolar Detection of Fe²⁺& Al³⁺Ions and Its Varied Applications

Abstract

A simple S−S (disulfide)-bridged dimeric Schiff base probe, L, has been designed, synthesized, and successfully characterized for the specific recognition of Al 3+ and Fe 2+ ions as fluorometric and colorimetric "turn-on" responses in a dimethylformamide (DMF)-H 2 O solvent mixture, respectively. The probe L and each metal ion bind through a 1:1 complex stoichiometry, and the plausible sensing mechanism is proposed based on the inhibition of the photoinduced electron transfer process (PET). The reversible chemosensor L showed high sensitivity toward Al 3+ and Fe 2+ ions, which was analyzed by fluorescence and UV−vis spectroscopy techniques up to nanomolar detection limits, 38.26 × 10 −9 and 17.54 × 10 −9 M, respectively. These experimental details were advocated by density functional theory (DFT) calculations. The practical utility of the chemosensor L was further demonstrated in electrochemical sensing, in vitro antimicrobial activity, molecular logic gate function, and quantification of the trace amount of Al 3+ and Fe 2+ ions in real water samples.

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