Electro-optical properties of poly(2-ethynyl-N-propargylpyridinium compound) with different counter ions

Poly(2-ethynylpyridinium bromide) with propargyl side chain (PEP–Br) was prepared by the direct polymerization of 2-ethynylpyridine and propargyl bromide under mild reaction conditions without any additional initiator or catalyst. The ion-exchanged products of PEP–Br were prepared by the simple ion-exchange reaction using ion-exchange reagents such as NaBPh4, NaClO4, and NaN3. The ion exchanged three polymers (PEP–PC, PEP–AZ, PEP–TPB) were found to be mostly insoluble in water and methanol, whereas the PEP–Br and PEP–TsO were completely soluble in the above solvents. Various instrumental analyses on the polymer structures indicated that the present polymers have a conjugated polymer backbone system having N-propargylpyridyl substituents with different counter ions. The photoluminescence intensity of the present ionic conjugated polymers increased as the temperature was increased. The photoluminescence peaks of the present ionic conjugated polymers were found to be located at 610–720 nm, depending on the counter anions.