Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080, China
Abstract:
A new non-ionic water-soluble polyfluorene that contains two benzo-18-crown-6 side chains per repeat unit (PFDC) is synthesized and characterized. Upon addition of Pb2+ ions to a solution of PFDC, the PFDC fluorescence is strongly quenched. The minor interference from other metal ions, especial from Cu2+ and Hg2+ions, clearly shows that the PFDC can be used to detect Pb2+ ions with high selectivity. The fluorescence quenching of PFDC in solution originates from the multivalent coordination of the crown-ether moieties to Pb2+ ions followed by precipitation. In comparison to ionic conjugated polymers, the pH of the medium shows less effect on the binding of non-ionic PFDC to Pb2+ ions.
