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RESEARCH PRODUCT

Synthesis, Structure and Solvatochromism of the Emission of Cyano-Substituted Oligo(phenylenevinylene)s

subject

description

Strongly luminescent and highly soluble oligo(phenylenevinylene)s with five benzene rings and cyano groups in different positions of the terminal styrene units were prepared by means of Horner and Knoevenagel reactions. The substitution pattern − cyanide moieties on the vinyl or on the aromatic regions, together with the effect of auxochromic groups − has distinct influences on the electronic spectra, particularly on the fluorescence. Polar solvents induce red shifts and strongly reduce the fluorescence intensity of the vinyl-substituted oligomers. Cyano substitution increases the electron affinity of the oligomers; this effect is more pronounced for molecules with vinyl cyanides and can be altered by the presence of additional electron-donating or electron-withdrawing groups. The molecular structures of one oligomer bearing cyano groups on the vinylene segments and one with benzonitrile units have been resolved.