Constrained geometry tetramethylcyclopentadienyl-phenoxy titanium complexes: Synthesis, structures and catalytic properties for ethylene polymerization
作者:Jian-Sheng Xu、Yue-Tao Zhang、Guang-Hua Li、Ying Mu、Shou-Hua Feng
DOI:10.1016/j.poly.2006.05.015
日期:2006.11
The synthesis of a new bidentate ligand, 1-(2-methoxyphenyl)-2,3,4,5-tetramethyl-cyclopentadiene (1), as well as its corresponding constrained geometry titanium complex, 2-tetramethylcyclopentadienyl-phenoxytitanium dichloride [(TCP)TiCl2, 2], was described. Complex 2 was synthesized by reaction of TiCl4 With the lithium salt of 1, followed by CH3Cl elimination at 65 degrees C. Molecular structures of 2 and a known complex, 2-tetramethylcyclopentadienyl-6-methyl-phenoxytitanium dichloride [(TCMP)TiCl2, IVd], were determined by single-crystal X-ray diffraction. The Cp(cent)-Ti-O angles of 107.4 degrees for 2, 107.0 degrees for IVd reveal their sterically open features as catalyst precursors. When activated with Al'Bu-3 and Ph3C+B(C6F5)(4)(-), complex 2 exhibits reasonable catalytic activity for ethylene polymerization, producing polyethylenes with moderate molecular weights and melting points. (C) 2006 Elsevier Ltd. All rights reserved.