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Oscillating Non‐Metallocenes – from Stereoblock‐Isotactic Polypropylene to Isotactic Polypropylene via Zirconium and Hafnium Dithiodiphenolate Catalysts
Author(s) -
Cohen Ad,
Goldberg Israel,
Venditto Vincenzo,
Kol Moshe
Publication year - 2011
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201100776
Subject(s) - tacticity , zirconium , polymerization , polymer chemistry , microstructure , chemistry , polypropylene , catalysis , metallocene , octahedron , copolymer , materials science , crystallography , organic chemistry , crystal structure , polymer
Abstract Octahedral group 4 complexes of a new bulky tetradentate dithiodiphenolate {OSSO}‐type ligand that oscillate between two enantiomeric C 2 ‐symmetric conformations are described. The dibenzyl Zr and Hf complexes led to active catalysts in propylene polymerization. Polypropylene having predominantly stereoblock‐isotactic microstructure or predominantly isotactic microstructure could be obtained by varying the polymerization conditions. Long isotactic blocks of 50 to more than 100 repeat units were formed at –10 °C in liquid propylene.