Electrochemical and spectral properties of thienylene- polyparaphenylenevinylene derivative stereoisomers

Four new compounds: 1,4-dimetoxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene), 1,4-dietoxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene), 1,4-isopropyloxy-2,5-bis[2- (tien-2-yl)ethenyl]benzene) and 1,4-dietoksy-2,5-bis[2-(5-methylthiophen-2-yl) ethenyl]benzene are synthesized. Three steroisomers ZZ, EZ and EE are isolated from the reaction mixture for the first two of them. Third compound is fully converted to the most stable EE form. Polymerization of all isomers leads to identical polymeric product. Mechanism of polymerization is recognized by using model molecule with methyl substituents blocking α-, α -sites. All seven stereoisomers have photoluminescent properties. Detailed spectral and electrochemical studies reveal isomerization phenomena during oxidation or at light exposure.