A Novel Conjugated Polymer Consists of Benzimidazole and Benzothiadiazole: Synthesis, Photophysics Properties, and Sensing Properties for Pd2+

A conjugated polymer PPBIBTE based on benzimidazole and benzothiadiazole was synthesized through palladium-catalyzed sonogashira cross-coupling reaction. The chemical structures of the monomers and the polymer were indicated by H-1 NMR, and investigation of photophysics properties and sensing optical properties for metal ions were observed by ultraviolet-visible and photoluminescence spectroscopy. PPBIBTE showed remarkable selectivity for Pd2+ by "turn-off" fluorescence sensing progress. In addition, the Stern-Volmer and Benesi-Hildebrand plots were used to reveal the interaction between the polymer and Pd2+, while job's method was applied to calculate the determination of stoichiometry. The results demonstrate that PPBIBTE can utilize static quenching for Pd2+ by forming a 1:1 complex. And it is a potential sensing material as fluorescence chemosensor for Pd2+ with high selectivity and sensitivity.