SYNTHESIS OF ZIRCONOCENE SILSESQUIOXANE COMPLEXES AND THEIR ETHENE POLYMERIZATION ACTIVITY IN SYSTEMS WITH METHYLALUMINOXANE

摘要

Protocols for obtaining defined zirconocene complexes with polyhedral oligomeric silsesquioxanes with mono-, di-, and trisilanol functionality (SIPOSS, DIPOSS, and TRIPOSS) were established. The TRIPOSS silanolates binding one zirconocene and one chlorozirconocene moiety, [{(c-C^sub 5^H^sub 9^)^sub 7^Si^sub 7^O^sub 9^O^sub 3^}Zr^sub 2^Cl(η^sup 5^-C^sub 5^H^sub 4^R)^sub 4^] (1, R = Bu; 2, R = H), were obtained by reacting the silanol with the respective zirconocene dichloride and triethylamine in CH^sub 2^Cl^sub 2^ in a 1.0:3.0:3.0 molar ratio, an excess of the zirconocene dichloride being required to suppress intramolecular dehydration of TRIPOSS. The related SIPOSS complex, [{(c-C^sub 5^H^sub 9^)^sub 7^Si^sub 8^O^sub 12^O}^sub 2^ - Zr(η^sup 5^-C^sub 5^H^sub 4^Bu)^sub 2^] (3), was prepared similarly at the stoichiometric ratio of [ZrCl^sub 2^(η^sup 5^-C^sub 5^H^sub 4^Bu)^sub 2^]/ SIPOSS/NEt^sub 3^ equal to 1.0:2.0:2.0. When employed in the 1.0:1.0:1.0 ratio, the same reagents afforded only the impure complex [{(c-C^sub 5^H^sub 9^)^sub 7^Si^sub 8^O^sub 12^O}ZrCl(η^sup 5^-C^sub 5^H^sub 4^Bu)^sub 2^] (4), contaminated with 3 and unreacted [ZrCl^sub 2^(η^sup 5^-C^sub 5^H^sub 4^Bu)^sub 2^]. Finally, the zirconocene complexes with SIPOSS and DIPOSS moiety, [{(c-C^sub 5^H^sub 9^)^sub 7^Si^sub 8^O^sub 12^O}^sub 2^Zr(η^sup 5^-C^sub 5^H^sub 5^)^sub 2^] (5) and [(c-C^sub 5^H^sub 9^)^sub 7^Si^sub 7^O^sub 9^(OSiMe^sub 3^)O^sub 2^}- Zr(η^sup 5^-C^sub 5^H^sub 5^)^sub 2^] (6), respectively, were obtained by reacting [ZrMe^sub 2^(η^sup 5^-C^sub 5^H^sub 5^)^sub 2^] with stoichiometric amounts of the appropriate silanols. All complexes were characterized by ^sup 1^H, ^sup 13^C, ^sup 29^Si NMR and IR spectra, and by elemental analysis from XPS spectra. Preliminary ethene polymerization experiments showed that compounds 5 or 6 when combined with an excess of methylaluminoxane were nearly as active as [ZrCl^sub 2^(η^sup 5^-C^sub 5^H^sub 5^)^sub 2^] whereas compound 2 was by about one order of magnitude less active. [PUBLICATION ABSTRACT]