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Metallocene/polypropylene structural relationships: Implications on polymerization and stereochemical control mechanisms
Author(s) -
Ewen John A.,
Elder M. J.,
Jones R. L.,
Haspeslagh Luc,
Atwood Jerry L.,
Bott Simon G.,
Robinson Kerry
Publication year - 1991
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19910480121
Subject(s) - polypropylene , metallocene , polymerization , materials science , polymer science , polymer chemistry , composite material , polymer
A series of group 4 metallocenes possessing chiral ligand environments have been characterized and their structures are compared with their propylene polymerizations. Isotactic, syndiotactic, hemiisotactic, and atactic polypropylenes are produced selectively with chiral monoalkyl metallocene cations paired with perfluorotetraphenyl borate; analogous to the results obtained using methylaluminoxane as a cocatalyst. The relative catalyst stereospecificities suggest specific π‐face selectivities and nonbonded contacts. Trends with solvents, temperatures, and catalyst structures are consistent with contact ion pairing for iPr[CpFlu]Zr‐P(+) in liquid propylene. The specificities of differently structured metallocenes imply chain‐migratory monomer addition reactions.