with the Cr metal. On activation with methylaluminoxane, the Cp-based complexes showed high catalytic activities for ethylene polymerization. High molecular weight polymers with unimodal molecular weight distributions were obtained, indicating that the nature of the polymerization was single site. The copolymerization of ethylene with norbornene by the pre-catalysts 2a–d was also explored in the presence
一系列半夹心
铬(的III)络合物轴承双(亚
氨基)
吡咯配体,CP'[2,5-C 4 H ^ 2 N(CH NAR)2 ]的CrCl [CP'= C 5 H ^ 5中,Ar = C 6 ħ 5(图2a),2,6--ME 2 ç 6 ħ 3(图2b),2,6-我
镨2 ç 6 ħ 3(图2c),C 6 ˚F 5(2D); CP'= C 5 Me 5,Ar = C 6 H5(图3a),2,6-我
镨2 ç 6 ħ 3( 3C)]以良好的收率合成。除了元素分析外,还通过FTIR和质谱对复合物进行表征。2a–c的X射线结构分析结果表明,
铬配合物具有伪八面体配位环境,具有三足的“钢琴凳”几何形状。亚
氨基氮原子之一与Cr
金属配位。在用甲基铝氧烷活化后,基于CP的络合物对
乙烯聚合反应显示出很高的催化活性。获得具有单峰分子量分布的高分子量聚合物,表明聚合的性质是单中心的。还研究了在甲基铝氧烷存在下
乙烯与
降冰片烯通