Synthesis and characterization of alternating copolymers containing bipyridine and phenylene vinylene for fluorescent chemosensors

Alternating copolymers containing bipyridine and phenylene vinylene were synthesized through a Wittig condensation reaction of their corresponding diphosphonium salts and dialdehydes. The molecular weights of the resulting polymers were relatively low because of the low solubility in the reaction solvents. The optical properties of the polymers were substantially affected by the repeating units of phenylene vinylene. The absorption spectra of the copolymers in the solid state exhibited a bathochromic shift compared to those carried out in solution. The effective conjugation length could be extended with the addition of Cu2+, Ni2+, and Zn2+ ions into the polymer solutions in a 1:1 ratio of the bipyridine to the phenylene vinylene units. All of the polymer solutions behaved as a turn-off fluorescent chemosensor upon the addition of a variety of the metal ions. The sensing behavior to various metal ions revealed that the polymers were highly sensitive to the Cu2+, Ni2+, and Zn2+ ions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42795.