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Fluxional behavior and polymerization activity of the new α , α′ ‐ ortho ‐xylene‐bis(5,6‐dimethyl‐1‐indenyl)zirconium dichloride
Author(s) -
Santi Roberto,
Abis Luigi,
Sommazzi Anna,
Zani Carla,
Proto Antonio,
Ricci Giovanni,
Millini Roberto,
Masi Francesco
Publication year - 2002
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(200207)203:10/11<1301::aid-macp1301>3.0.co;2-#
Subject(s) - methylaluminoxane , metallocene , polymer chemistry , zirconium , ethylene , chemistry , polymerization , tacticity , post metallocene catalyst , molar mass distribution , catalysis , copolymer , crystallography , polymer , organic chemistry
We synthesize a new ortho ‐xylenyl‐bridged substituted metallocene catalyst which surprisingly affords ethylene‐1‐hexene copolymers with broad molecular weight distribution (MWD), when activated with methylaluminoxane (MAO). In order to investigate the reasons of this behavior we carry out an in‐depth study on the metallocene complex. Its structure is determined by X‐ray crystallography and found to have C 1 symmetry in the solid state. Variable temperature 1 H NMR suggests the existence in solution of a slow conformational exchange between two identical C 1 structures. Therefore, the broad MWD has been ascribed to the presence of two conformationally blocked, single‐site catalysts.Interconversion of C 1 catalysts through a C 2 catalyst.