867197-46-4Relevant academic research and scientific papers
Group 4 metallocene complexes with non-bridged and tetramethyldisiloxane- bridged methyl-phenyl-cyclopentadienyl ligands: Synthesis, characterization and olefin polymerization studies
Martínez, Gema,Royo, Pascual,Mosquera, Marta E.G.
, p. 4395 - 4406 (2004)
meso- and rac-Diastereomers of the Me-Ph-cyclopentadienyl-disubstituted zirconocene and tetramethyldisiloxane-bridged ansa-metallocene dichlorides (M = Zr, Hf) have been isolated by transmetallation of their lithium salts to MCl4 and characterized by NMR spectroscopy and X-ray diffraction methods. The zirconocene dichlorides activated with MAO are active catalysts for ethene and propene polymerization. The non-vicinal methyl-phenyl-substituted zirconocene dichlorides meso-and rac-[Zr{η5-(1-Ph-3-Me-C 5H3)}2Cl2] and [Zr(η 5-C5H5){η5-(1-Ph-3-Me-C 5H3)}Cl2] have been isolated by transmetallation of the lithium salt Li(1-Ph-3-Me-C5H3) to ZrCl4(THF)2 and [Zr(η5-C5H 5)Cl3 ? DME] (DME = dimethoxyethane), respectively. Similar transmetallation of the lithium salt Li2[(Me-Ph-C 5H2SiMe2)2O] to MCl4 gave the ansa-metallocenes [M{η5-(Me-Ph-C5H 2SiMe2)2O}Cl2] (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{η5-(2-Me-4-Ph-C5H2SiMe 2)2O}Cl2] was determined by single crystal X-ray diffraction methods. The activity of the dichlorometallocenes/MAO catalysts for ethene and propene polymerization was evaluated.
