Synthesis, characterization, and catalytic properties of ansa-zirconocenes [Zr{1-Me2Si(3-η5-C9H5R) 2}Cl2] (R = Me, nPr, nBu, and Bz)

Carlos Alonso-Moreno, Antonio Antiñolo, Fernando Carrillo-Hermosilla, Antonio Otero*, Ana M. Rodríguez, José Sancho, Victoria Volkis, Moris Eisen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The ansa-indene ligands {1-Me2Si(3-C9H 6R)2} [R = Me (1), nPr (2), nBu (3), and Bz (4)] were prepared by alkylation of the unsubstituted ansa-indene. These ligands were converted, by reaction with nBuLi, to the di-lithium compounds [Li 2{1-Me2Si(3-C9H5R)2}] [R = Me (5), nPr (6), nBu (7), and Bz (8)]. ansa-Zirconocenes, [Zr{1-Me 2Si(3-η5-C9H5R) 2}Cl2] [R = Me (9), nPr (10), nBu (11), and Bz (12)], have been prepared by the reaction of ZrCl4 with 5-8 in diethyl ether/toluene at -78°C. The molecular structure of meso-[Zr{1-Me 2Si[3-η5-C9H5(CH 3)]2}Cl2] (9) and rac-[Zr{1-Me 2Si[3-η5-C9H5-(CH 2CH2CH3)]2}Cl2] (10) have been determined by single-crystal X-ray diffraction studies. Ethylene polymerization catalysis has been studied for complexes 9-12 as a mixture of meso and rac isomers in the presence of methylaluminoxane (MAO) as cocatalyst. Complexes 9-12 exhibit high activities and give rise to polyethylene with low molecular weights without the introduction of molecular hydrogen. In addition, active species from these complexes were found to be very stable in comparison with unsubstituted analogues.

Original languageEnglish
Pages (from-to)972-979
Number of pages8
JournalEuropean Journal of Inorganic Chemistry
Issue number5
DOIs
StatePublished - 6 Mar 2006
Externally publishedYes

Keywords

  • Ethylene
  • Homogeneous catalysis
  • Metallocenes
  • Polymerization
  • Zirconium

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