All-trans oligomers of 2,5-dialkyl-1,4-phenylenevinylenes–metathesis preparation and characterization

✍ Scribed by Emma Thorn-Csányi; Peter Kraxner

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 765 KB
• Volume: 198
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1997.021981205

✦ Synopsis

Abstract

Oligomers of 2,5‐dialkyl‐1,4‐phenylenevinylenes (DR‐OPV, R = C~4~H~9~, C~7~H~15~, C~10~H~21~ and C~6~H~11~) (CyH) were prepared via metathesis polycondensation of the respective 2,5‐dialkyl‐1,4‐divinylbenzenes. The synthesis of the monomers is described. The highly active metal‐alkylidene complex Mo(NAr)(CHCMe~2~Ph)[OCMe(CF~3~)~2~]~2~ (Ar = 2,6‐dimethylphenyl) serves as a catalyst. The degree of polymerization can be controlled by variation of the solvent and by the length of the side chains, since the reaction proceeds as a precipitation polycondensation. The DR‐OPVs are bilious‐green products and, depending on the molecular weight, soluble in various solvents like toluene, THF and CHCl~3~. The solutions are highly fluorescent and coloured. The DR‐OPVs have vinylic end groups. The vinylene double bonds are of all‐trans configuration. Due to their rigid‐rod structure, the DR‐OPVs synthesized have a distinct tendency to crystallize in a highly ordered state, forming a sanidic layer structure.