Cyclopolymerization of 1,5-hexadiene catalyzed by various stereospecific metallocene compounds

Cyclopolymerization of 1,5-hexadiene has been carried out at various temper atures in toluene by using three different stereospecific metallocene catal ysts-isospecific rac-(EBI)Zr(NMe2)(2) [EBI: ethylenebis(1-indenyl), Cat 1], syndiospecific Me2C(Cp)(Flu)ZrMe2 (Cp = 1-cyclopentadienyl, Flu 1-fluoreny l, Cat 2), and aspecific Cp-2*ZrMe2 (Cp*: pentamethylcyclopentadienyl, Cat 3) compounds in the presence of Al(i-Bu)(3) and [Ph3C][B(C6F5)(4)-in order to study the effect of polymerization temperature and catalyst stereospecif icity on the property and microstructure of poly(methylene-1,3-cyclopentane ) (PMCP). The activities of catalysts decrease in the following order: Cat I > Cat 2 > Cat 3. PMCPs produced by Cat 1 are net completely soluble in to luene. but those by Cat 2 and Cat 3 are soluble in toluene. trans-Diisotact ic rich PMCPs are produced by Cat I and Cat 2, and cis-atactic PMCP by Cat 3. The cis/trans ratio of PMCP by Cat I and Cat 2 is relatively insensitive to the polymerization temperature, but that by Cat 3 is highly sensitive t o the polymerization temperature. Melting temperatures of PMCP produced inc rease with the cis to trans ratio of rings. (C) 2000 John Wiley & Sons, Inc .