Heterogeneous constrained-geometry zirconium catalysts

Heterogeneous constrained-geometry catalysts were prepared by immobilizing Zr(NMe2)a on a heterogenized ansa-cyclopentadienylamino ligand of type (RN) R'R"Si(C5R"'(4)): surface 1, R = -O-Me2Si(CH2)(3); R', R", R"' = Me; surfac e 2, R = -O-Me2Si(CH2)(3); R', R"' = Me, R" = a The preparation of the cons trained-geometry catalyst ligand on a silica surface has been carried out i n two steps: first: functionalizing the silica surface with aminopropyldime thylethoxysilane (APDMES) by using saturated gas-solid reactions, and then immobilizing two different (tetramethylcyclopentadienyl)chlorosilan Me2Si(C 5Me4H)Cl and MeHSi(C5Me4H)Cl, on the APDMES-functionalized silica by utiliz ing n-BuLi (n-butyllithium). Zr(NMe2)(4) was immobilized on the heterogeneo us surfaces using the amine elimination reaction. The two heterogeneous mon ocyclopentadienylamido zirconium catalysts were characterized with H-1, C-1 3, and Si-29 solid-state NMR and FTIR spectroscopy and tested for ethylene polymerization.