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.

Dual responsive pyridoxal-AHMT based fluorescent sensor towards zinc(ii) and mercury(ii) ions and its bioimaging application

“…One is a flexible turn-on switching functionality probe towards Zn 2+ ions and another probe is a highly fluorescent ratiometric sensor for Na + ions. 22,23 Both the sensors worked well even in the solid state. The previous results encouraged us to further design a novel probe based on the pyridoxal-AHMT moiety.…”

“…25 Moreover, other pyridoxal based probes have also been reported in the literature for the detection of Zn 2+ , Cu 2+ , Fe 2+ , Na + and Ag + . 22,23,26 AHMT (4-Amino-3-hydrazino-5-mercapto-1,2,4-triazole), also known as purpald, is a heterocyclic compound which has different functional groups such as primary amine, thioamide and hydrazyl groups, and hence, it exhibits a polar structure; 27 it is conventionally used for colorimetric detection of formaldehyde. 28 Recently aminoglycoside antibiotic agent kanamycin was detected by using gold nanoparticles-copper nanoclusters where AHMT acts as a fluorescence quencher in the assay.…”

“…25 Moreover, other pyridoxal based probes have also been reported in the literature for the detection of Zn 2+ , Cu 2+ , Fe 2+ , Na + and Ag + . 22,23,26…”