Copolymer of Fluorene and Triphenylamine Moieties: Direct and Post-Functionalization Strategy, Structural Characterization, and Chemosensoring Behavior

To prepare a copolymer of fluorene and triphenylamine bearing imidazole groups in the side chain, two synthetic approaches have been designed: the direct copolymerization of the corresponding monomers, and the post-functionalization of a precursor polymer. Unexpectedly, the direct copolymeriztion strategy was better. The chemosensing behavior of P2 was carefully studied, the fluorescence of which could be quenched by Cu2+ ions at concentrations as low as 8 x 10(-6) mol.L-1 in dilute solutions. By utilizing the much higher stability constant of the complex of CN- and Cu2+, the quenched fluorescence of the solution of P2 by Cu2+ ions could be recovered upon the addition of a trace amount of CN- anions, with a detection limit as low as 1.8 x 10(-5) mol.L-1 (0.47 ppm), making P2 a new sensitive cyanide probe.