文献类型：期刊文献

英文题名：Highly Thermally Stable Eight-Coordinate Dichloride Zirconium Complexes Supported by Tridentate [ONN] Ligands: Syntheses, Characterization, and Ethylene Polymerization Behavior

作者：Li, Aike[1];Ma, Haiyan[1];Huang, Jiling[1]

机构：[1]E China Univ Sci & Technol, Lab Organometall Chem, Shanghai 200237, Peoples R China

年份：2013

卷号：32

期号：24

起止页码：7460

外文期刊名：ORGANOMETALLICS

收录：;EI(收录号：20141317509882);WOS:【SCI-EXPANDED(收录号:WOS:000329137900026)】；

基金：We are grateful for support from the National Natural Science Foundation of China (No. 21274041 and 20774027) and the key project of the Chinese Ministry of Education (No. 109064).

语种：英文

外文关键词：Chlorine compounds - Zirconium compounds - Single crystals - X ray diffraction - Ethylene - Thermodynamic stability - Synthesis (chemical) - Catalyst activity - Polymerization

摘要：A series of novel eight-coordinate dichloride zirconium complexes with the general formula L2ZrCl2 supported by two tridentate [ONN] ligands have been synthesized by the reaction of ZrCl4 center dot 2THF with 2 equiv of the corresponding ligands (tridentate phenoxy-imine ligands ((LH)-H-1-(LH)-H-4) or tridentate phenoxy-amine ligands ((LH)-H-5-(LH)-H-6)). These complexes were characterized by NMR and elemental analyses. The molecular structures of representative zirconium complexes C2 and C6 were confirmed by single-crystal X-ray diffraction and revealed that the metal center is eight-coordinated by two tridentate [ONN] ligands and two chlorides in a distorted-square-antiprismatic geometry. When C1-C6 were activated by modified methylaluminoxane (MMAO), the resultant catalysts displayed notable thermal stability and high activities toward ethylene polymerization. The ligand substituents, the metal coordination environment, and the reaction conditions had a profound effect on the polymerization. The catalytic activity increases consistently with increasing polymerization temperature, and the highest activity of 1.04 X 10(6) g of PE (mol of Zr)(-1)h(-1) was achieved in o-xylene at 140 degrees C. A catalytic lifetime of nearly 5 h was observed for the C5/MMAO catalyst system at 140 degrees C.