Schiff Base–Tethered Silane as a Trifunctional Probe for Selective Ni ² ⁺ Sensing, Antioxidant Activity, and Molecular Docking

ABSTRACT In this study, a new Schiff base‐functionalized silane, compound 3, derived from 4‐(pyridin‐2‐yl)benzaldehyde, was synthesized and comprehensively characterized using 1 H NMR, 13 C NMR, and mass spectrometry. The optical properties of compound 3 were investigated via UV–visible and fluorescence spectroscopy, demonstrating high selectivity and sensitivity toward Ni 2+ ion with minimal interference from other metal ions. Job's plot confirmed a 1:1 binding stoichiometry, while the binding constants were determined as 7.91 × 10 7 M −1 (Stern–Volmer) and 3.12 × 10 7 M −1 (Benesi–Hildebrand), indicating strong metal–ligand interactions. The limits of detection were exceptionally low: 0.17 (fluorescence) and 3.7 nM (absorption), supporting ultra‐trace detection capability. The binding mechanism was further validated by 1 H NMR titration, mass spectrometry, and density functional theory calculations. Pharmacokinetic predictions via ADMET tools suggested favorable bioavailability, while antioxidant activity assays demonstrated significant radical‐scavenging efficiency. Molecular docking with an antioxidant target protein (PDB ID: 1HD2) revealed a binding energy of −7.41 kcal mol −1 , supporting the experimental results. Real‐sample analysis confirmed the practical application of compound 3 in detecting Ni 2+ ion in environmental water samples. These findings establish compound 3 as a multifunctional platform with promising applications in environmental monitoring and biomedical research.