Polymerization of p-diethynylbenzene catalyzed by (π-C5H5)(PPh3)Ni(CCC6H4CCH)

Homogeneous polymerization of p-diethynylbenzene (p-DEB) with (π-C5H5)(PPh3)Ni(CCC6H4CCH) catalyst has been investigated in terms of added compound, reaction atmosphere, catalyst and monomer concentration and polymerization temperature. The single-component and environmentally stable nickellocene acetylide is an effective catalyst for the p-DEB polymerization, and the polymerization can proceed under mild conditions to give soluble and stable polymers in high yields. The polymerization rate equation can be expressed as Rp=kp[M][cat]1.4, where kp=0.58 l1.4 mol−1.4 min−1 (40°C). The overall polymerization activation energy was found to be 84 kJ mol−1. Poly(p-diethynylbenzene) so obtained possesses weight average molecular weights as high as 55 700 and an extended π-conjugated polyene chain structure with pendent groups of p-C6H4CCH.