A phenothiazine-based "naked-eye" fluorescent probe for the dual detection of Hg2+ and Cu2+: Application as a solid state sensor

Abstract

A phenothiazine-based colorimetric and fluorescent probe (3) for Hg2+ and Cu2+ was designed and synthesized. Probe 3 showed high selectivity and sensitivity toward Hg2+ and Cu2+ over other metal ions. This probe works as a chemodosimeter based on the Kucherov reaction for the selective detection of Hg2+. Copper recognition is based on soft soft metal interactions with the -S and -N atoms of the probe 3. Probe 3 exhibited a red-shift in the absorption spectra from 449 to 606 nm for Hg2+ and at 612 nm for Cu2+ that is accompanied by significant color changes from orange to dark blue and blackish-blue. Probe 3 could be used as a solid state (test paper, TLC plates) optical sensor for the selective detection of Hg2+ and Cu2+. The binding process was confirmed by UV-vis absorption, fluorescence measurements, IR, H-1 NMR and mass spectroscopy. (C) 2015 Elsevier Ltd. All rights reserved.