Synthesis of 2,2 '-bipyridine-containing polymers: synthesis of poly[2,2 '-bipyridine-4,4 '-diylethynylene-(2,5-dialkoxy-1,4-phenylene)ethynylene]

Novel 2,2'-bipyridine-based conjugated polymers of formula 2 have been synt hesized by Pd-catalyzed cross-coupling reactions between 4,4'-dibromo-2,2'- bipyridine (3) and substituted phenyldiacetylenes (4). The zig-zag arrangem ent of the 2,2'-bipyridine units implies a helical conformation of 2. The s olubility of 2 requires at least a dodecyl side-chain. 2 is thermostable up to 400 degreesC. The polymers have a high fluorescence quantum yield in so lution (60%).