Polymer-based fluorescence sensor incorporating thiazole moiety for direct and visual detection of Hg2+ and Ag+

A thiazole-based conjugated polymer was synthesized by the polymerization reaction of 4,7-dibromo-2-methylbenzo[d]thiazole with 1,4-diethyny1-2,5-bis(octyloxy)benzene via Pd-catalyzed Sonogashira coupling reaction. The conjugated polymer emits bright green fluorescence and exhibits 'turn-off' fluorescent quenching responses towards both Hg2+ and Ag+ over other cations, such as Li+, K+, Ca2+, Mg2+, Ba2+, Zn2+, Cd2+, Co2+, Ni2+, Pb2+, Cu2+, Al3+ and Fe3+. More importantly, the color change of this polymer solution could be clearly observed by the naked eyes upon the addition of Hg2+ (green to colorless) and Ag+ (green to yellow), indicating that this thiazole-based conjugated polymer material could be used as a calorimetric sensor for directly visual detection of Hg2+ and Ag+. (C) 2015 Elsevier Ltd. All rights reserved.