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 synthesized by Pd-catalyzed cross-coupling reactions between 4,4′-dibromo-2,2′-bipyridine (3) and substituted phenyldiacetylenes (4). The zig-zag arrangement of the 2,2′-bipyridine units implies a helical conformation of 2. The solubility of 2 requires at least a dodecyl side-chain. 2 is thermostable up to 400°C. The polymers have a high fluorescence quantum yield in solution (60%).