Conformational effects on electrical and spectroscopic properties of 1,2-di(2-thienyl)ethylenes and corresponding poly[(2,2′-dithienyl)-5,5′-diylvinylenes]

✍ Scribed by Tiziana Benincori; Elisabetta Brenna; Franco Sannicolò; Licia Trimarco; Gilberto Schiavon; Sandro Zecchin; Gianni Zotti

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 574 KB
• Volume: 197
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1996.021970208

✦ Synopsis

Abstract

1,2‐Dialkyl‐substituted 1,2‐di(2‐thienyl)ethylenes have been synthesized and investigated by cyclic voltammetry. The bulk of the alkyl substituents was modulated in order to progressively increase the torsional angle between the thiophene rings and the plane of the olefinic bond, from a fully planar structure to highly twisted systems. Distortion markedly affects the UV spectra and the oxidation peak potentials of the monomers. The electro‐chemical polymerization experiments gave the following results: (i) (E)‐ and (Z)‐dithienyl‐ethylene systems produced polymers with identical properties; (ii) progressive deviation from planarity increased the oxidation peak potential of the monomer, as far as the polymerization was inhibited; (iii) long and rigid monomeric units reduced chain flexibility, leading to materials with low conductivity and unsatisfactory mechanical properties.