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Abstract: Carbazole was electropolymerized on indium tinoxide (ITO) electrodes in two air- and water-stable room-temperature ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF6) and N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide (BMP-TFSI), respectively, using three potentiostatic methods (i.e., cyclic voltammetry, potentiostatic electrolysis, and potentiostatic pulse electrolysis). The polymer films obtained in both ionic liquids (ILs) adhered on the electrode surface well; however, the polycarbazole (PCz) films obtained in the more viscous BMI-PF6 exhibited a denser structure. The PCz films showed electrochromic behavior; deep green was observed in the oxidative state and pale green in the reductive state. Anions or viscosities of the ILs seem to influence the depth of color change. PCz films were also prepared under a normal atmosphere. [Copyright &y& Elsevier]

Abstract Two electropolymerizable carbazole-functionalized viologen compounds were synthesized and characterized using NMR, ESI-MS, voltammetry, and spectroelectrochemistry. The compounds were electropolymerized onto indium tin oxide electrode and glassy carbon electrode through a radical-induced polymerization triggered by electrochemical oxidation at the carbazole moieties in electrolytes composed of room temperature ionic liquid/organic solvents or NaClO 4 /acetonitrile. It was found that the properties of the electropolymerized polymers were crucially controlled by the chemical structure of the monomer and the electrolyte compositions. The polymer films showed electrochromic behavior, and the color changed from greenish at the potential where carbazole groups were oxidized to violet or colorless at which reduction of viologen groups occurred; violet or colorless depended on which of the two reductive states of the viologen moieties was reached. The polymer films were capable of enhancing the oxidative current of uric acid and ascorbic acid, respectively, in neutral media, which might be due to the concentrating ability of the viologen moieties towards negatively charged species such as ferricyanide ([Fe(CN) 6 ]3−) and ferrocyanide ([Fe(CN) 6 ]2−). Graphical abstract Unlabelled Image Highlights • Carbazole substituted viologen was prepared as electropolymerizable monomers. • Monomers with mono- or di-carbazole groups were prepared. • Single-backbone or two-backbone conducting polymers could be formed. • Not only the monomer structures but the electrolytes control the polymer properties. • The polymers show the electrochromic and anion-adsorptive behavior. [ABSTRACT FROM AUTHOR]