Synthesis of oct-OPV5 and Ooct-OPV

Oct-OPV5 and Ooct-OPV5 were prepared following a procedure that was used to prepare terf-butyl-end-substituted oligo(phenylene vinylenes) [43], Benzyltri-phenylphosphonium bromide was lengthened by a styryl unit via a Wittig reaction with 4-methylbenzaldehyde. The methyl group of the stilbene was functionalized by bromination with A -bromosuccinimide (NBS). The phosphonium salt of the stilbene was obtained by a subsequent reaction with triphenylphosphine in toluene. 

The cyano-substituted five-ring oligomers were formed in good yields in a Knoevenagel condensation between an aldehyde and a cyanomethyl-substituted compound, according to a procedure previously reported by Greenham et al. [6]. The Knoevenagel condensation needs careful control of reaction conditions in order 

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