Mononuclear aluminum hydroxide for the design of well-defined homogeneous catalysts
Mononuclear aluminum hydroxide for the design of well-defined homogeneous catalysts
复制标题
DOI：
10.1021/ja043585w
复制
发表时间：
2005-03-16
影响因子：
15
通讯作者：
Schmidt, HG
中科院分区：
文献类型：
--
作者：
Bai, G;Singh, S;Schmidt, HG
以三氯化铝为原料，通过水解法合成了一种新型氢氧化铝Laime(OH)(5；L=HC[(CME)(2，6-IPR(2)C(6)H(3)N)](2))。在5的制备中，使用了KOH、水和Kh1的试剂以及氨/甲苯两相体系。在甲苯中，5与CP2ZrMe2(8)和Cp2ZrHCl进一步反应，高产率地消除了CH4和H-2的分子间反应，生成了Mu-O桥联的双核铝和锆络合物[Laime(Mu-O)ZrMeCp2](6)和[La1Me(Mu-O)ZrClCp2](7)。晶体结构表明，5是末端带有羟基和Me基团的单体。X-射线结构分析表明，6和7具有弯曲的Al-(Mu-O)-Zr核，末端为Al-Me和Zr-Me或Zr-Cl排列。甲基铝氧烷(MAO)活化的化合物6和7对乙烯聚合表现出很高的催化活性。在相似的聚合条件下，MAO/6和MAO/7催化剂体系表现出比MAO/8更高的活性和更低的MAO：催化剂比。
An unprecedented aluminum hydroxide LAIMe(OH) (5; L = HC[(CMe)(2,6-iPr(2)C(6)H(3)N)](2)) has been prepared by the hydrolysis of LAlMeCl (4). For the preparation of 5, the reagents of KOH, water, and KH1 as well as the two-phase ammonia/toluene system, were used. Further reactions of 5 with CP2ZrMe2 (8) and Cp2ZrHCl in toluene lead to the intermolecular elimination of CH4 and H-2 and the formation of mu-O-bridged dinuclear aluminum and zirconium complexes [LAIMe(mu-O)ZrMeCp2] (6) and [LA1Me(mu-O)ZrClCP2] (7), respectively, in high yields. The crystal structure reveals that 5 is a monomer with terminal OH and Me groups. The X-ray structure analysis shows that 6 and 7 contain a bent Al-(mu-O)-Zr core with terminal Al-Me and Zr-Me or Zr-Cl arrangements. The methylalumoxane (MAO)-activated compounds 6 and 7 exhibit high catalytic activity for the polymerization of ethylene. Under comparable polymerization conditions, the MAO/6 and MAO/7 catalyst systems show considerably higher activity and much lower MAO:catalyst ratios than that of MAO/8.