|
Abstract: (Chemical Abstract 1998, 129:16418)
|
|
The unbridged complexes bis(h(5)-(1-para-fluoro benzyl)indenyl)
MCl2 (2: M = Hf; 3: M = Zr) as well as their ethylene bridged analogues
bis[(h(5)-3-(1-para-fluoro benzyl)indenyl)ethane]
MCl2 (4: M = Hf; 5: M = Zr)
have been synthesized and the obtained rac- and meso-isomers were separated from
the 1:1 isomer mixtures. Complexation was performed by converting the ligand precursors
(1-para-fluoro benzyl)indene 1a and bis(3-(1-para-fluoro benzyl)indenyl)ethane
1b into their lithio salts and further treatment with MCl4.
To study the influence of the para-fluoro benzyl substituent in ethene polymerization,
the catalyst precursors 2-5 were activated with methylalumoxane (MAO) and their
polymerization behavior was compared to corresponding unsubstituted metallocenes.
The crystal structure of meso-like 3 was determined by means of X-ray structure analysis,
showing a central/lateral: gauche-type orientation of its para-fluoro benzyl substituents
in the solid state.
|
|
|
|
|
