Macromolecular Rapid Communications, Vol.22, No.13, 1072-1075, 2001
Microstructure of highly syndiotactic "living" poly(propylene)s produced from a titanium complex with chelating fluorine-containing phenoxyimine ligands (an FI catalyst)
Highly syndiotactic "living" poly(propylene)s were synthesized at 25 degreesC using a bis[N-(3-tertbutylsalicylidene)-2,3,4,5,6-pentafluoroanilinato)titanium (IV) dichloride/MAO catalyst system, axed microstructures of the polymer were analyzed by means of C-13 NMR spectroscopy: The syndiotactic poly(propylene) contains isobutyl, isopentyl and propyl end groups, suggesting that the living polymerization of propylene was initiated via 1,2-insertion, followed by 2,1-insertion as the principal mode of polymerization. Pentad distribution analysis revealed that the syndiospecific polymerization proceeds under chain-end control.