ansa-Zirconocene Complexes with Modified Benzindenyl Ligands:  Syntheses, Crystal Structure, and Properties as Propene Polymerization Catalysts^1,2

Abstract

As modifications of the effective catalyst precursor [dimethylsilanediylbis(benz[e]indenyl)]zirconium dichloride, the ansa-zirconocene complexes Me2Si(cyclopenta[c]phenanthryl)2ZrCl2, Me2Si(cyclopenta[l]phenanthryl)2ZrCl2, Me2Si(2-methylcyclopenta[l]phenanthryl)2ZrCl2, and Me2Si(2-methyltetrahydrobenz[e]indenyl)2ZrCl2 have been synthesized. When activated by methylaluminoxane (MAO), these complexes give highly active catalysts for the polymerization of propene to polymers with high isotacticities and molecular weights.

Molybdenum complexes containing substituted cyclopenta[l]phenanthrenyl ligand

“…Spectroscopic data are in agreement with those reported previously [16]. 13 Compound 3 (1.7 g, 5 mmol) was diluted with 30 ml of THF, cooled at 0°C and treated dropwise with 3.1 ml of n-BuLi (1.6 mol l -1 ).…”

“…Condensation of compound 2 with pyrrolidine gives cyclopenta[l]phenanthrene substituted with both methoxycarbonyl and tert amino functions (3). 2-Methyl-1H-cyclopenta[l]phenanthrene (6) was prepared from compound 4 in line with the previously described procedure [16].…”

“…)[16] were prepared according to literature procedures 1. H and 13 C{ 1 H} NMR spectra were measured in CDCl 3 and CD 3 CN solutions on Bruker Avance 400 spectrometer at room temperature.…”

Synthesis and molecular structures of zirconium and hafnium complexes bearing dimethylsilandiyl-bis-2,4,6-trimethylindenyl and dimethylsilandiyl-bis-2-methyl-4,6-diisopropylindenyl ligands

“…Ansametallocenes with 4,7-disubstituted indenyl ligands have been recently described [2][3][4]. Complexes with benzoannelated indenyl residue were prepared as well [2][3][4][5][6][7][8]. Meanwile, synthesis of the compounds with 4,6-disubstituted indenyl fragments has not been described so far.…”

Methylbenz[e]indenyl asymmetric ansa-metallocene and silylamido zirconium complexes

“…It has been extensively demonstrated [1] that the clever selection of an appropriate ligand is a decisive step in achieving the best results from the catalytic system. It is well known that the presence of aromatic six-membered rings in indenyl ligands and their derivatives induces a remarkable increase in the catalytic activity of indenyl metallocenes, and that the introduction of a 2-alkyl substituent in these molecules hinders the b-elimination that favors the production of polymers of higher molecular weight [2,3].…”