Chiral <i>Ansa</i> Metallocenes with Cp Ring-Fused to Thiophenes and Pyrroles: Syntheses, Crystal Structures, and Isotactic Polypropylene Catalysts
作者:John A. Ewen、Michael J. Elder、Robert L. Jones、Arnold L. Rheingold、Louise M. Liable-Sands、Roger D. Sommer
DOI:10.1021/ja004266h
日期:2001.5.1
Syntheses, crystal structures, and polymerization data for new isospecific metallocenes (heterocenes) having cyclopentenyl ligands b-fused to substituted thiophenes (Tp) and pyrroles (Pyr) are reported. The C2- and C1-symmetric heterocenes are dimethylsilyl bridged, have methyl groups adjacent to the bridgehead carbon atoms, and have aryl substituents protruding in the front. rac-Me2Si(2,5-Me2-3-P
报道了具有与取代的噻吩 (Tp) 和吡咯 (Pyr) 稠合的环戊烯基配体的新型同种特异性茂金属(杂茂)的合成、晶体结构和聚合数据。C2-和C1-对称的杂茂是二甲基甲硅烷基桥接的,有甲基与桥头碳原子相邻,并且有芳基取代基突出在前面。rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2/MAO(MAO = 甲基铝氧烷)是迄今为止报道的聚丙烯最活跃的茂金属催化剂。rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2 和 rac-Me2Si(2,5-Me2-1-Ph-4-Cp[b]Pyr)2ZrCl2结构,前者的活性高 6 倍,产生的总对映面误差减半,在相同条件下丙烯聚合中的区域特异性低 3.5 倍。rac-Me2Si(2-Me-4-Ph-1-Ind)2ZrCl2/MAO 为 3。活性比 rac-Me2Si(2,5-Me2-3-Ph-6-Cp[b]Tp)2ZrCl2