Synthesis and electronic spectra of substituted p-distyrylbenzenes for theuse in light-emitting diodes

The influence of substitution on the absorption and Luminescence spectra of oligo(phenylenevinylene)s has been studied using distyrylbenzene (DSB) as a model compound. The degree, character, and pattern of substitution was va ried systematically, altering the electronic properties of the DSB, the wav elength of the emitted light could be tuned over a range of 100 nm. The syn theses of 6b-h were performed by twofold Wittig-Horner-olefinations of bisp hoshonates 1a, b with substituted benzaldehydes 2a-i, 6i via Heck-reaction of the dibromosulfonylbenzene 3, 6k by Siegrist-reaction of 4 with N-phenyl benzaldimine and the Knoevenagel-reaction of benzyl cyanide with 5 led to 6 l.