title: Introduction of methyl groups on vinylene segments of phenylene vinylene systems: synthesis and properties.
abstract: A facile synthetic route towards phenylene vinylene systems with methyl substituents at the vinyl linkages is demonstrated through palladium catalyzed Heck coupling of 1,4-diisopropenylbenzene with aryl bromides. The coupling leads to a series of model compounds that feature, in some cases, direct access to a trans-configuration at the double bonds. The oxidative stability of these systems is surprisingly unaffected by the presence of allylic C-H bonds in the methyl substituents. The methyl substituents modulate the electronic properties of the phenylene vinylene systems by inducing a significant twist to the conjugated backbone. The study suggests that the introduction of methyl groups at vinylene sites is a viable alternative to functionalising and tuning the properties of phenylene vinylene systems.
authors.affiliation: Institute of Materials Research and Engineering (IMRE), and the Agency for Science, Technology and Research (A*STAR), 3 Research Link Singapore 117602, Republic of Singapore.
authors.forename: Khai Leok
authors.initials: KL
authors.lastname: Chan
authors.forename: Alan
authors.initials: A
authors.lastname: Sellinger