Silsesquioxane-bonded zirconocene complexes; soluble models for silica-tethered olefin polymerization catalysts

Abstract

Silsesquioxane tethered fluorene ligands [R 7 Si 8 O 12 X]-9-Flu(H) (R = c-C 6 H 11 , X = -( 1 and [(c-C 5 H 9 ) 7 Si 8 O 12 CH 2 -9-Flu] 2 ZrCl 2 (9) have been applied as models for silicatethered ancillary ligands and silica tethered-zirconocenes. Immobilization of zirconocenes containing a pendant anchorable functionality, CpЉ[Me 2 (EtO)SiCH 2 Flu]ZrCl 2 (10) and Cp[C 5 Me 4 SiMe 2 OEt]ZrCl 2 (11) was considerably hampered by competitive Zr-Cl and Si-OEt bond splitting. When activated with MAO (methylalumoxane), 6-9 yield active ethylene polymerization systems.

Versatile Phosphite Ligands Based on Silsesquioxane Backbones

“…It is only the second crystal structure of a monofunctionalized, completely condensed silsesquioxane framework, the first one bearing an alkyl linker instead of the oxo group. [25] The geometry around the platinum atom in complex 4 is only slightly distorted square planar, as can be concluded from the angles P1 À Pt À P2 of 178.36(9)8 and Cl1 À Pt À Cl2 of 178.74(12)8. Both silsesquioxane groups are located on the same side of the molecule.…”

Dumbbell‐Shaped T8‐POSS with Functional Organic Linkers

“…In 2003, Severn et al reported the synthesis of silsesquioxane‐bonded zirconocene complexes by reacting partially condensed silsesquioxane with triethoxysilane‐substituted molecules to afford the corner‐capped POSS substituted compound. Applying this synthetic route to compounds 5 and 8 failed to produce the corresponding dumbbell‐shaped POSS and no reaction occurred probably because the reactivity towards partially condensed T 7 ‐triol is lower than these with the zirconocene derivative.…”

Preparation of Novel Materials for Catalysts Utilizing Metal-Containing Silsesquioxanes

“…With regard to the group 4 transition metal-containing silsesquioxanes, the catalytic activities for various reactions, i.e. the epoxidation of alkenes [2][3][4][5][6][7][8][9][21][22][23][25][26][27][28] and polymerization of small alkenes [2,3,16,17,[35][36][37][38], have been reported. In the course of our study on the preparation of novel group 4 metal-containing silsesquioxanes, we have successfully synthesized titanocenecontaining silsesquioxanes (2a-c) for the first time (equation 3) [39].…”