A benzoindo-croconine based colorimetric and fluorescent chemosensor for detection Fe3+/Cu2+/Ag+ ions

A benzoindo-croconine based fluorescent and colorimetric chemosensor for Fe3+,Cu2+ and Ag+ ions was synthesized and characterized. It showed sensitive recognition and significant selectivity to Fe3+, Cu2+ and Ag+ ions in C2H5OH/H2O (4:1, v/v). Upon the addition of Fe3+ ion, the color of solution changed from brownness to pale yellow. The fluorescence intensity decreased with the increased concentration of Fe3+, and the fluorescence was completely quenched as the concentration of Fe3+ ion was up to 0.4 mM. Moreover, the fluorescence of the benzoindo-croconine was also quenched with the increased concentration of Cu2+/Ag+ ions. In order to clarify the binding mechanism of Fe3+/Cu2+/Ag+ ions with benzoindo-croconine chemosensor, the H-1 NMR spectra and the voltammetric behaviors of the benzoindo-croconine upon the addition of Fe3+/Cu2+/Ag+ ions were performed. The FESEM results indicated that the coordination behavior of Fe3+, Cu2+ and Ag+ ions to the ligand of the benzoindo-croconine owned characteristic of multi-particle aggregates. (C) 2015 Elsevier GmbH. All rights reserved.