Small‐Molecule Fluorescent Probe: Ratiometric and Selective Detection of Sodium Ions for Imaging and Solid‐State Sensing Applications

Abstract A ratiometric highly fluorescent small molecular probe ( L ), 1,2,4‐triazol‐4‐yliminomethyl‐5‐(hydroxymethyl)‐2‐methylpyridin‐3‐ol , was designed for detecting Na(I) ions in DMF:water (1 : 9, v/v) medium. The chemical structure of Na(I) complex of probe was confirmed by single crystal XRD. The fluorescence detection of Na + ion has been executed in both solid and solution medium. The observations suggest the same chemical structure in solution state as well. The detailed photochemical studies showed that highly selective sensing of Na + ions even in the presence of common interfering K + ions. The fluorescence decay studies showed that the lifetime of NaL is lesser than L . The excited state intramolecular proton transfer (ESIPT) mechanism and the nature of electronic transitions were examined by quantum chemical studies. The electrochemical behaviour was studied by cyclic voltammetry and impedance spectra. It has also been shown that the probe can be applied to paper based sensing and imaging of Na + ions in U87 cell lines.