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Selective Dimerization of γ ‐Branched α ‐Olefins in the Presence of C 2 v Group‐4 Metallocene‐Based Catalysts
Author(s) -
Boccia Antonella C.,
Costabile Chiara,
Pragliola Stefania,
Longo Pasquale
Publication year - 2004
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/macp.200400174
Subject(s) - methylaluminoxane , metallocene , monomer , chemistry , cyclopentadienyl complex , polymer chemistry , reactivity (psychology) , zirconium , catalysis , polymerization , organic chemistry , polymer , medicine , alternative medicine , pathology
Abstract Summary: The oligomerization of γ ‐branched α ‐olefins in the presence of catalytic systems based on group‐4 metallocenes with C 2 v symmetry has been investigated. The highest reactivity was obtained by using dimethylsilyl‐bis(cyclopentadienyl)zirconium‐dichloride activated by methylaluminoxane. Highly regioregular dimers were selectively obtained for hindered γ ‐branched monomers, while the less hindered ones produced higher molecular weight oligomers. A molecular modeling approach was used to rationalize the experimental results. In fact, a decrease in the β ‐hydrogen elimination barrier and an increase in the insertion barrier with the monomer bulkiness were calculated.General structure of the obtained dimers.