Group 4 metallocene complexes with non-bridged and tetramethyldisiloxane-bridged methyl-phenyl-cyclopentadienyl ligands: synthesis, characterization and olefin polymerization studies

Abstract

The non-vicinal methyl-phenyl-substituted zirconocene dichlorides meso-and rac- -(Me-Ph-C 5 H 2 SiMe 2 ) 2 O}Cl 2 ] (M = Zr, Hf) for which the meso-and rac-diastereomers were separated. The dimethyl and dibenzyl derivatives of these metallocenes were also prepared and the structure of all of these compounds determined by NMR spectroscopy. The molecular structure of rac-[Zr{g 5-(2-Me-4-Ph-C 5 H 2 SiMe 2 ) 2 O}Cl 2 ] was determined by single crystal X-ray diffraction methods. The activity of the dichlorometallocenes/MAO catalysts for ethene and propene polymerization was evaluated.

Synthesis and characterization of methyl-phenyl-substituted cyclopentadienyl zirconium complexes

“…However, few studies have been focused on the regioselectivity of reactions made to introduce a third substituent on any of the three possible positions of the 1-Ph-3-Me-cyclopentadiene or on the electronic and steric effects of the methyl and phenyl substituents and their relative location on the reactivity of the resulting metal complexes. In line with our interest in studying the steric and electronic effects of bulky ligands on the reactivity of their metallocene and cylopentadienylsilylg-amido group 4 metal complexes, we have reported [15] the use of the disubstituted Me-Ph-cyclopentadienyl ligand to prepare non-bridged and tetramethyldisiloxane-bridged group 4 metallocene complexes. We report herein the results observed when different silyl groups [SiMe 3 , SiMe 2 Cl, SiMe 2 (NHt-Bu) and SiMe 2 (Me-Ph-C 5 H 3 )] are introduced into the 1-Ph-3-MeC 5 H 4 ring and the structural consequences when the corresponding cyclopentadienyl ligand is used to prepare monocyclopentadienyl, ansa-dicyclopentadienyl and ansa-cyclopentadienyl-silyl-g-amido zirconium complexes.…”