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 Ksv 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.