Polymer, Vol.35, No.6, 1312-1316, 1994
Polymerization of 1,4-bis(Tetrahydrothiopheniomethyl)-2-Cyano-5-Methoxybenzene Dibromide - Synthesis of Electronically Push-Pull Substituted Poly(P-Phenylene Vinylene)S
The base-induced polymerization of 1,4-bis(tetrahydrothiopheniomethyl)-2-cyano-5-methoxybenzene dibromide in aqueous acetonitrile yields a soluble polyelectrolyte which may be thermally eliminated to give the electronically ’push-pull’ substituted poly(2-cyano-5-methoxy-1,4-phenylene vinylene). Ultraviolet-visible and infra-red spectral studies showed production of the conjugated polymer, with a band gap of ca. 2.6-3.0 eV (410-480 nm) that varied somewhat as a function of elimination conditions. Elemental analysis indicates some retention of tetrahydrothiophenium side groups in the polyelectrolyte polymer, despite the use of a variety of elimination conditions. The retention of side chains in this synthesis is possibly due to a significant degree of irregularity in the positions of the cyano and methoxy substituents in the eliminated polymer, resulting from non-regioselectivity in this polymerization. This reaction demonstrates the potential in the Wessling process for polymerization of p-xylylenes that have electronically very asymmetric (’push-pull’) substitution patterns.