STEREOCHEMICAL CONTROL IN PROPYLENE POLYMERIZATION WITH A ASYMMETRICALLY SUBSTITUTED TITANOCENE METHYLALUMINOXANE CATALYST/

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.