J. Tian et al., STEREOCHEMICAL CONTROL IN PROPYLENE POLYMERIZATION WITH A ASYMMETRICALLY SUBSTITUTED TITANOCENE METHYLALUMINOXANE CATALYST/, Science in China. Series B, Chemistry, life sciences & earth sciences, 38(9), 1995, pp. 1068-1074
A new mono-substituted titanocene, (eta(5)-cyclopentadienyl) [eta(5)-(
1-(4-methoxyphenyl) cyclohexyl) cyclopentadienyl] dichlorotitanium (I)
, has been prepared via a novel modified synthesis, and its X-ray crys
tal structure has been determined. It crystallizes in the orthorhombic
space group P2(1)2(1)2(1) with cell constants a=0.968 0(5) nm, b=1.28
4 6(5) nm, c=1.694 4(6) nm, Z=4, R=0.066. The I/methylaluminoxane (MAO
) catalyst system produces at different polymerization temperatures ei
ther an isotactic or a syndiotactic polypropylene, both of which have
the combined influence of enantiomorphic-site control and chain-end co
ntrol, or an atactic polypropylene controlled by Bernoullian propagati
on mechanism.