Ionochromic and potentiometric properties of the novel polyconjugated polymer from anodic coupling of 5,5′-bis(3,4-(ethylenedioxy)thien-2-yl)-2,2′-bipyridine

Anodic coupling of 5,5'-bis(3,4-(ethylenedioxy)thien-2-yl)-2,2'-bipyridine has produced a new ion-coordinating polyconjugated polymer as thin films on electrodes. The polymer has been characterized by cyclic voltammetry, FTIR reflection-absorption, UV-vis spectroscopy, electrochemical quartz crystal microbalance, in situ ESR, and in situ conductivity. The as-prepared polymer, which bears protonated bipyridine units, is reversibly oxidized with one electron every other bithiophene moiety and reduced in two complex steps to the neutral material. Deprotonation of the polymer films produces substrates able to coordinate protons and divalent transition metal ions (Fe2+, Co2+, Ni2+, and Cu2+) with corresponding spectral and redox changes. The ionochromic and potentiometric properties of the polymer films as prototype sensor materials are reported.