About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
Chemistry of Materials
Paper
ESR Characterization of Oligomeric Thiophene Materials
Abstract
The ESR of electrooxidation products of orthogonally bridged dimers of α,α-coupled thiophene oligomers and spiro-fused phenylene-thiophene mixed oligomers was studied as a function of temperature. ESR measurements on the one-electron oxidation products indicate that the charge remains on a single oligomer unit and does not hop between the two bridged oligomer chains for temperatures up to 300 K. This is evident from the presence of hyperfine structure in ESR spectra for the dimers of short-chain oligomers and the small temperature-dependent line broadening for longer chain spiro dimers, characteristic of a low-energy process such as the paramagnetic site moving along the oligomer chain length. The activation energy for a paramagnetic center moving along the oligomer chain length has been estimated at <100 cm−1. The incorporation of phenylene into the oligomer unit shifts oxidation potentials anodic and also inhibits the mobility of the pelaron along the πhconjugated oligomer segment. Evidence for formation of π-π dimers in solutions of 7-mT has also been obtained. © 1994, American Chemical Society. All rights reserved.