CONJUGATED IONIC POLYACETYLENES .3. POLYMERIZATION OF ETHYNYLPYRIDINIUM SALTS

A novel and simple method for polymerization of the acetylenic bond conjugated with or directly attached to a quaternizable heteroatom is described. The resulting polymers are black, amorphous solids, soluble in polar organic solvents and in water. Their solubility depends both on molecular mass and on the nature of the counterion. Unlike unsubstituted polyacetylene, they are more stable to air. The polymerization method is illustrated on examples involving polymerization of 2- and 4-ethynylpyridines and their derivatives. The acetylenic triple bond is sufficiently activated to undergo spontaneous polymerization leading to substituted, highly charged polyacetylenes with extensively conjugated backbones. Thus in contrast to previous reports, extensive substitution does not appear to affect long conjugation sequences in polyacetylenes.