Microstructure of highly syndiotactic 'living' poly(propylene)s produced from a titanium complex with chelating fluorine-containing phenoxyimine ligands (an FI catalyst)

摘要

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. [References: 45]