prepared in up to 93% yield. These compounds, activated with methyl aluminoxane, exhibit high active propene polymerization rates which remain constant over hours, even at elevated polymerization temperatures of 50 and 70 °C. The two different coordination sites of these “dual-side” catalysts lead to isotactic polypropenes with variable amounts of stereoerrors, depending on the monomer concentration. The
                                    新的 C1-对称配合物 rac-[1-(9-η5-
芴基)-2-(2-methylbenz[e]-1-η5-indenyl)ethane] 二
氯化
锆 (14a), rac-[1-(9 -η5-
芴基)-2-(4,5-环己-2-甲基-1-η5-
茚基)
乙烷]二
氯化
锆(14b)和外消旋-[1-(9-η5-
芴基)-2-( 5,6-环戊-2-甲基-1-η5-
茚基)
乙烷]二
氯化
锆(15)的制备产率高达93%。这些用甲基铝氧烷活化的化合物表现出高活性
丙烯聚合速率,即使在 50 和 70 °C 的升高聚合温度下,也能在数小时内保持恒定。这些“双侧”催化剂的两个不同配位点导致等规聚
丙烯具有不同数量的立体误差,具体取决于单体浓度。
茚基
配体的 2-甲基取代基同时产生,