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Anodic coupling of tris[5,5′-bis(3,4-(ethylenedioxy)thien-2-yl)-2,2′-bipyridine]M(ClO 4 ) 2 (M=Fe, Ru) has produced new ion-coordinating polyconjugated polymers. These polymers have been characterized by cyclic voltammetry, FTIR reflection-absorption spectroscopy, UV–vis spectroscopy, energy-dispersion X-ray analysis, electrochemical quartz crystal microscopy and in situ conductivity. The polymer films contain bis-coordinated bipyridyl complexes owing to ligand abstraction by protons produced in the coupling reaction. In situ conductivity versus potential is displayed at the oxidation redox potential as a redox-typical bell-shaped relationship with the maximum conductivities around 10 −4 S cm −1 . The electrodeposition of thick films is made possible by the proximity of the deposition voltage and the polymer redox potential, which makes the deposited material redox conductive. Owing to this reason, the corresponding cobalt and nickel complexes cannot be polymerized at all. Films of the polymeric complexes perform a normally efficient electrocatalytic reduction of carbon dioxide.

Anodic coupling of 4,4′(5′)-bis[(3,4-(ethylenedioxy)thien-2-yl]tetrathiafulvalene (1) in acetonitrile has produced a new polythiophene-based polymer containing tetrathiafulvalene (TTF) moieties regularly inserted in the polythiophene chain. The polymer poly(1) has been compared with poly(3-[7-oxa-8-(4-tetrathiafulvalenyl)octyl]-2,2′-bithiophene) bearing the TTF moieties as pendant groups. The polymer films were characterized by cyclic voltammetry, FTIR reflection–absorption and UV–vis spectroscopy, in situ ESR and in situ conductivity. The reversible oxidation of the polymers in two one-electron steps at the TTF moiety displays characteristics which suggest a faster electron transfer and a higher redox conductivity for poly(1).

A solid state cell proposed elsewhere, enabling the extension of ion exchange voltammetry to trace determination of small ionic species with low ion exchange selectivity coefficients, dissolved in electrolyte-free media, has been adopted to verify whether the degrees of preconcentration achieved with such a voltammetric technique actually increase with the decrease of the sample ionic strength—in agreement with thermodynamic expectations—or whether they are otherwise conditioned by kinetic complications. With this purpose, a series of experiments has been conducted by accumulating either monovalent or divalent cationic analytes (Tl+ and Pb2+) at glassy carbon electrodes modified with Nafion® films loaded with either monovalent or divalent cations (Na+ and Ca2+) from aqueous solutions containing different concentrations of both the analyte and the loading ion introduced as the cation of the supporting electrolyte. These preconcentrated ions were then assayed by inserting the modified electrodes in the solid state cell mentioned. The results obtained indicate that the expected inverse proportional relation between the degree of preconcentration achieved and the ionic strength of the sample analyzed is found only at fairly high concentrations of supporting electrolyte, the values of which depend on both the charge and concentration of the analyte as well as on the charge of the counterion from the supporting electrolyte. In contrast, at lower ionic strengths, the degree of preconcentration is kinetically controlled. This finding is discussed in terms of interdiffusion effects as well as of the decrease in both diffusion coefficients in the polymer and equilibrium constants, owing to cross-linking changes involved in the ion exchange processes. Also the outcome of such kinetic control on analytical determinations of trace ionic species in poorly conducting samples is considered.

Various methyl and methoxy monosubstituted and disubstituted anilines were electropolymerized in acidic conditions. From UV—visible absorption and electrochemical measurements, it has been found that methyl substituted anilines give polymers which are less planar than the methoxy derivatives. This has been explained in terms of more pronounced steric effects of the methyl group than those induced by the methoxy group. However, alkoxy monosubstituted anilines exhibit lower conductivities than those obtained with the alkyl derivatives. This has been explained by a less regular structure for poly(alkoxyanilines). Indeed, as shown by the cyclic voltammetry experiments, the selectivity of the head-to-tail couplings is reduced by the incorporation of a methoxy group at the ortho position. However, more regular materials have been obtained with 2,5-disubstituted polyanilines. For instance, poly(2,5-di-methoxyaniline) exhibits a high conjugation length and a good conductivity (ca. 0.3 S cm−1).