Homogeneous copolymerization of polar with nonpolar substituted acetylenes by palladium complex catalyst

The homogeneous copolymerization of nonpolar p-diethynylbenzene (DEB) with polar propargyl alcohol (OHP) by palladium complex catalyst [Pd(CCCH2OH)2(PPh3)2] (PPO) in CHCl3/methanol mixed solvents at 60 °C has been investigated for the first time to give a soluble copolymer. The composition of copolymers was determined by IR analysis and confirmed by 1H-NMR integration method. The reactivity ratio of the two monomers was calculated to be r1=0.89 (DEB) and r2=1.18 (OHP). The copolymerization of DEB with OHP by palladium catalyst is an ideal one having tendency of constant proportion copolymerization. A mechanism of step coordination insertion was proposed for the copolymerization.