Cyclopolymerization of 2-ethynyl-N-propargylpyridinium tetraphenylborate by transition metal catalysts

A new conjugated ionic cyclopolymer having a bulky tetraphenylborate counter ion, poly (2-ethynyl-N-propargylpyridinium tetraphenylborate), was synthesized via ring-forming polymerization of the corresponding diacetylenic monomer. The polymerization of 2-ethynyl-N-propargylpyridinium tetraphenylborate was performed using various transition metal catalysts. In general, the polymerization of this diacetylenic monomer proceeded well to give a high yield of polymer. The catalytic activities of a W-based catalyst were similar with those of Mo-based catalysts. The resulting polymers were mostly brown or black powders. The polymer structure was characterized through elemental analysis and NMR, IR, and UV-visible spectroscopies to confirm the conjugated cyclopolymer structure and its tetraphenylborate counter ions. The inherent viscosities of the resulting polymers were in the range 0.09 similar to 0.16 dL/g, depending on the polymerization conditions. The thermal and morphological properties of the polymers were also studied and are discussed.