A NEW CLASS OF CONJUGATED IONIC POLYACETYLENES .3. CYCLOPOLYMERIZATION OF ALKYLDIPROPARGYL(4-SULFOBUTYL)AMMONIUM BETAINES BY TRANSITION-METAL CATALYSTS

A new type of conjugated ionic polyacetylene was synthesized by metath esis polymerization of betaine monomers, alkyldipropargyl(4-sulfobutyl )ammonium betaines (ADPSAB). The alkyl groups used are ethyl, n-butyl, n-hexyl, and n-octyl. The polymerization of ADPSAB was carried out wi th various transition metal catalyst systems such as MoCl5-, WCl6-, an d PdCl2-based catalyst systems. The MoCl5 and PdCl2 were found to be p articularly effective catalysts for the cyclopolymerization of the bet aine monomers. H-1-NMR, C-13-NMR, IR, and UV-visible spectroscopies sh owed that poly(ADPSAB) possess polyene structure having cyclic recurri ng units in the polymer backbone. Unlike polyelectrolyte, the resultin g polymers were more soluble and showed higher viscosities in the salt solution than in salt-free solution (antipolyelectrolytes). When dope d with an acceptor such as iodine, the polymers exhibited a substantia l increase (similar to 10(-3) S/cm) in electrical conductivity compare d to the undoped state (similar to 10(-10) S/cm).