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“Oscillating” Metallocene Catalysts: How Do They Oscillate?
Author(s) -
Busico Vincenzo,
Cipullo Roberta,
Kretschmer Winfried P.,
Talarico Giovanni,
Vacatello Michele,
Van Axel Castelli Valeria
Publication year - 2002
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/1521-3773(20020201)41:3<505::aid-anie505>3.0.co;2-j
Subject(s) - metallocene , propene , monomer , polymerization , oscillation (cell signaling) , polypropylene , catalysis , tacticity , polymer chemistry , chemistry , post metallocene catalyst , materials science , crystallography , chemical physics , organic chemistry , polymer , biochemistry
Rather than involving the rac ‐like (chiral) and meso ‐like (achiral) conformations , as commonly believed, the “oscillation” of [(2‐Ar‐indenyl) 2 ZrCl 2 ] propene polymerization catalysts takes place within the rac ‐like conformation, between its two enantiomorphous forms with opposite enantioselectivities. The result is the peculiar polypropylene microstructure shown, which degenerates into a (quasi‐)atactic form when the “oscillation” is faster than monomer insertion.