A bipyridine-containing water-soluble conjugated polymer: Highly efficient fluorescence chemosensor for convenient transition metal ion detection in aqueous solution

A novel sulfonato-functionalized water-soluble conjugated polymer (WSCP), which containing 2′2-bipyridine units as receptors for transition metal ions in the main chain was successfully synthesized by Sonogashira-coupling reaction for the first time. This polymer could easily dissolve in water (5 mg/mL) and some polar organic solvents such as methanol. Its fluorescence in aqueous solution can be completely quenched upon addition of transition metal ions. The K_sv of different transition metal ions in aqueous solution were much higher than previous reports in organic solutions and showed highest selectivity to Ni²⁺. These results opened opportunities for developing novel chemosensors by introducing selective fluorescent chromophore into the water-soluble conjugated backbone.