Silane‐Grafted Schiff Base for Selective Ni(II) Detection: Optical Sensing, Cytotoxicity on HeLa Cells, and Its Real Sample Evaluation

ABSTRACT A novel silane–grafted Schiff base derivative, designated as compound 3 , was synthesized and thoroughly characterized using 1 H NMR, 13 C NMR, FT‐IR, and mass spectrometry. The formation of its Ni(II) complex was confirmed by FT‐IR, mass spectrometry, and DFT calculations. Photophysical studies revealed that compound 3 exhibits excellent selectivity and sensitivity toward Ni(II) ions, with low detection limits of 2.6 × 10 −8 M (UV–Vis) and 3.0 × 10 −10 M (fluorescence). DFT analysis supported the experimental findings, indicating the formation of a stable and energetically favorable complex. The compound also showed high accuracy in detecting Ni(II) in real water samples and exhibited low cytotoxicity toward HeLa cells, suggesting potential applications in both environmental monitoring and biological sensing. Overall, compound 3 functions as a stable, sensitive, and multifunctional fluorescent probe for Ni(II) ion detection.