Polymer-based fluorescent sensor incorporating 2,2′-bipyridyl and benzo[2,1,3]thiadiazole moieties for Cu2+ detection

The polymer was synthesized by the polymerization of 4,4′-((4-iodophenoxy)methyl)-2,2′-bipyridine (M-1) with 4,7-diethynylbenzo[2,1,3]-thiadiazole (M-2) via Pd-catalyzed Sonogashira reaction. The fluorescence responses of the polymer towards various transition metal ions were investigated by fluorescence spectra and UV–Vis spectra. The polymer shows green fluorescence under ultraviolet lamp, which can be quenched by Cu2+ completely due to the heavy metal effect. The results suggested that the polymer can be used as a Cu2+-selective sensor via a naked eyes detecting mode.

Graphical abstractThe polymer shows a strong fluorescence emission centered at 515 nm. With the addition of Cu2+ from 0.05 to 0.50 molar ratio, the fluorescence intensity was quenched steadily.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A polymer-based fluorescent sensor is synthesized via Sonogashira coupling reaction. ► The sensor exhibits high sensitivity and selectivity towards Cu2+. ► The fluorescence changing can be easily detected by naked eyes under ultraviolet lamp.