Novel C1 symmetric zirconocenes containing substituted indenyl moieties for the stereoregular polymerization of propylene

• Published in: Journal of organometallic chemistry Vol. 688; no. 1; pp. 153 - 160
• Main Authors: Esteb, John J., Chien, James C.W., Rausch, Marvin D.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2003
• Subjects: Asymmetric metallocenes; Isotactic polypropylene; Olefin polymerization; Zirconocenes; Asymmetric metallocenes; Olefin polymerization; Zirconocenes; Isotactic polypropylene
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/j.jorganchem.2003.08.040

The synthesis and polymerization behavior of four new asymmetric ansa-metallocenes containing a fluorenyl moiety and a substituted indenyl moiety is reported. The zirconocenes diphenylsilylene-(η 5-9-fluorenyl)-[η 5-1-(3- t-butyl)indenyl]-zirconium dichloride ( 4), dimethylsilylene-(η 5-9-fluorenyl)-[η 5-1-(3- t-butyl)indenyl]-zirconium dichloride ( 5), ethylene-1-(η 5-9-fluorenyl)-2-[η 5-1-(3- t-butyl)indenyl]-zirconium dichloride ( 6), and diphenylsilylene-(η 5-9-fluorenyl)-[η 5-1-(2-methyl-4-phenyl)indenyl]-zirconium dichloride ( 8) were all found to be highly active for the polymerization of both ethylene and propylene when activated with excess methylaluminoxane. Compound 8 was found to produce highly isotactic polypropylene with an [mmmm] value of 83%. Four new asymmetric ansa-metallocenes containing a fluorenyl moiety and a substituted indenyl have been synthesized and evaluated as catalyst precursors for the polymerization of ethylene and propylene when activated with methylaluminoxanes. In the case of propylene, stereoregular polymer was obtained.