The effect of 2,2-dicyanovinyl groups as electron acceptors in push-pull substituted oligo(1,4-phenylenevinylene)s

The newly synthesized oligo(1,4-phenylenevinylene) series 2a-d with bis(2-hexyloctyl)amino groups as electron donors and 2,2-dicyanovinyl groups as electron acceptors represents conjugated oligomers with strong push-pull effects. Due to the decrease of the intramolecular charge transfer with increasing numbers of repeat units (n=1-4), the long-wavelength transition shows a particularly great hypsochromic shift for the extension of the chromophore.