Highly selective propylene dimerization catalyzed by C₁‐symmetric zirconocene complexes

Abstract

A series of ethylene-bridged C 1 -symmetric ansa-(3-R-indenyl)(fluorenyl) zirconocene complexes (1-9) incorporating a pendant arene substituent on the 3-position of indenyl ring have been synthesized. The structure of complex 4 was further confirmed by X-ray diffraction analysis. When activated with methylaluminoxane, four sterically less encumbered complexes 1, 2, 4 and 5 could catalyze the dimerization of propylene in toluene at 100°C to afford 2-methyl-1-pentene with high selectivities up to 95.7-98.4% and moderate activities of 2.00 × 10 4 to 7.89 × 10 4 g (mol-ZrÁh) À1 .

Synthesis of Ethylene-Bridged Bis(indenyl) Zirconium, Hafnium Complexes and Their Catalytic Behavior on Selective Propylene Oligomerization: the Effect of 3-Substituent on Indenyl Ring

“…2014 年, 我们课题组 [24] 在茚环 3-位引入含有悬垂 苯环结构的取代基, 得到了一系列亚乙基桥联型茚-芴 锆配合物, 发现当悬垂基团具有枯基结构时, 配合物在 甲基铝氧烷(MAO)活化下能够高选择性地催化丙烯选 择性二聚, 其中 2-甲基-1-戊烯含量最高达到 98%, 但配 合 物 普 遍 催 化 活 性 很 低 , 仅 为 2.0×10 4 ～ 7.9×10 4 g•mol-Zr -1 •h -1 . 在此基础上, 我们将茚环 3-位的枯基结 构延伸为苄基结构, 得到了分子量为 300～20000 g/mol 的丙烯齐聚物或聚合物, 并意外地发现所得丙烯齐聚物 具有非常高的烯丙基端基选择性 [25][26] , 最高可以达到 91%.…”