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Published June 2, 1993 | public
Journal Article

Voltammetric characterization of soluble polyacetylene derivatives obtained from the ring-opening metathesis polymerization (ROMP) of substituted cyclooctatetraenes


High molecular weight, amorphous, partially substituted polyacetylenes (poly-RCOT) have been prepared using the ring-opening metathesis polymerization of substituted cyclooctatetraenes. Spin-cast films of these polymers yielded unusually sharp, well-defined, reversible electrochemistry for oxidative and reductive doping processes. As the substituent on the polymer chain was varied (R = alkyl, tert-butoxy, trimethylsilyl, and p-X-phenyl), the potentials for oxidative and reductive doping changed by 0.3 V. In addition, the separation between the oxidative and reductive doping processes varied from 1.66 V to >2.0 V. Coulometry suggested that the reversible doping step represented a transfer of 1 electron for every 13-15 double bonds of the polymer. In contrast, the electrochemistry of predominantlycis poly-RCOT films was irreversible, and indicated the presence of an electrochemical cis-trans isomerization on the first voltammetric sweep through either reductive or oxidative doping. Spectroelectrochemical studies indicated that the electrochemically doped poly-RCOT materials (R = sec-butyl, (CH₃)₃Si) possessed mid-gap transitions at energies of 0.8-0.9 eV. The redox chemistry of the soluble, poly-RCOT (R = sec-butyl, (CH₃)₃Si) species in CH₂C1₂ solution was also investigated. Voltammetric studies showed that both the reductive and oxidative doping processes were chemically irreversible, and indicated that the dissolved polymers were electroactive over a wide range of potentials.

Additional Information

© 1993 American Chemical Society. We acknowledge the Office of Naval Research (R.H.G.) and the National Science Foundation (N.S.L. Grant CHE-8814694; R.H.G. and N.S.L. joint, Grant CHE-9202583) for support of this work. We also wish to thank the IBM Corp. (E.J.G.), the American Chemical Society Division of Organic Chemistry (C.B.G.), and Smith Kline & French Laboratories (C.B.G.) for research fellowships. We also thank Professor F. C. Anson for helpful discussions and the reviewers for suggestions regarding the possible effects of Fermi level shifts on the absorption spectra of the polyenes.

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August 20, 2023
October 19, 2023