Design, Synthesis, and Application of a Novel Schiff Base‐1,2,3‐triazole Fluorescent Probe for Selective Detection of Aluminum Ions

ABSTRACT A novel fluorescent “turn‐on” probe, N′‐((2‐hydroxynaphthalen‐1‐yl) methylene)‐5‐methyl‐2‐phenyl‐2H‐1,2,3‐triazole‐4‐carbohydrazide (G 3 ), was designed and synthesized. The structure was fully characterized by 1 H NMR, 13 C NMR, and MS. G 3 exhibits highly selective and sensitive fluorescence enhancement toward aluminum ions in aqueous solution. Job's plot analysis, 1 H NMR titration, and mass spectrometric studies confirm a 1:1 binding stoichiometry between G 3 and Al 3+ , which is further supported by density functional theory (DFT) and quantum chemical calculations elucidating the sensing mechanism. Notably, the probe achieves an exceptionally low detection limit of 1.162 nM, outperforming most previously reported Al 3+ sensors. Practical applicability was demonstrated through Al 3+ detection in environmental water samples and the development of a portable swab test kit. Cytotoxicity assays reveal low cellular toxicity, while fluorescence imaging in HeLa cells and zebrafish confirms its biocompatibility and bioimaging capability. These results highlight G 3 as a promising probe with high sensitivity, excellent selectivity, and significant potential for applications in environmental monitoring and biological sensing.