Rationally constructed imidazole derivatized Schiff-base based fluorescent sensor for reversible identification of copper ions and its applications in fingerprint imaging

A new imidazole-based optical probe 2-((2-(benzo[d]thiazol-2-yl)hydrazono)methyl)-6-(4,5-diphenyl-1 H-imidazol-2-yl)phenol (BMIP) as a colorimetric and fluorimetric chemosensor for detection of Cu2+ ions was synthesized and characterized by NMR spectra and mass spectra analysis. When exposed to Cu2+ ions in an aqueous environment even in presence of other cations, the probe BMIP exhibited striking color changes via a fluorescence-off process only for Cu2+ ions. The detection limit of Cu2+ was found to be 7.84 nM with response time as low as 10 s. In addition, BMIP-Cu2+ was found to be a reversible sensor with the addition of Ethylenediaminetetraacetic acid (EDTA). Experiments with test strips and with real water samples showed that the probe BMIP holds promise for identification of environmental ions. Density Functional Theory (DFT) computations with the Gaussian 16 software were employed to examine the BMIP sensing mechanism. The experimental findings were theoretically validated by DFT calcula-tions. The application of BMIP as a Cu2+ sensor has been extended to live cell and fingerprint imaging.(c) 2023 Elsevier B.V. All rights reserved.