Binuclear half-metallocene chromium(III) complexes mediated ethylene polymerization with alkylaluminium as cocatalyst.
Binuclear half-metallocene chromium(III) complexes mediated ethylene polymerization with alkylaluminium as cocatalyst.
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DOI：
10.1039/c1dt10803d
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发表时间：
2011-08
影响因子：
4
通讯作者：
Tieqi Xu;Yutian Pan;Xiao‐Bing Lu
中科院分区：
文献类型：
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作者：
Tieqi Xu;Yutian Pan;Xiao‐Bing Lu
双核半茂金属铬配合物{Cp*[3-（CH==NR）-2-O-C（10）H（5）]CrCl}（2）[Cp* = C（5）Me（5）; R =（i）Pr（1），Ph（2），2，6-（i）Pr（2）C（6）H（3）（3）]，以及它们的单核类似物Cp*[3-（CH==NR）-2 '-R'-2-O-C（20）H（11）]CrCl [R =（i）Pr，R' =（n）BuO（4），R = Ph，R' =（n）BuO（5），R = 2，6-（i）Pr（2）C（6）H（3），R' =（n）BuO（6），R =（i）Pr，R' = H（7）]，并通过质谱、元素分析、磁性测量和紫外-可见光谱进行了表征。通过单晶X射线晶体学分析进一步证实了配合物1、3、5和6的分子结构。当用少量AlMe（3）活化时，这些双核配合物与它们的单核类似物相比显示出更高的催化乙烯聚合活性，提供具有单峰分子量分布的高分子量聚合物。在亚胺氮原子上带有2，6-（i）Pr（2）C（6）H（3）基团的配合物3催化体系中，在25 equiv. AlMe（3）作为活化剂在20 °C下。(13)C NMR分析表明，所得聚合物是线性的，没有发现分支的证据。
Binuclear half-metallocene chromium complexes {Cp*[3-(CH==NR)-2-O-C(10)H(5)]CrCl}(2) [Cp* = C(5)Me(5); R = (i)Pr (1), Ph (2), 2,6-(i)Pr(2)C(6)H(3) (3)] based on 1,1'-binaphthyl ligands, as well as their mononuclear analogues Cp*[3-(CH==NR)-2'-R'-2-O-C(20)H(11)]CrCl [R = (i)Pr, R' = (n)BuO (4), R = Ph, R' = (n)BuO (5), R = 2,6-(i)Pr(2)C(6)H(3), R' = (n)BuO (6), R = (i)Pr, R' = H (7)], were synthesized and characterized by mass spectrometry, elemental analysis, magnetic measurement, and UV-vis spectroscopy. The molecular structures of complexes 1, 3, 5 and 6 were further confirmed by single-crystal X-ray crystallographic analysis. When activated with a small amount of AlMe(3), these binuclear complexes exhibited higher activities in catalyzing ethylene polymerization in comparison with their mononuclear analogues, affording high molecular weight polymers with unimodal molecular weight distributions. The highest activity up to 2.87 × 10(6) g PE (mol Cr)(-1) h(-1) was achieved in the catalyst system of complex 3 bearing a bulky 2,6-(i)Pr(2)C(6)H(3) group on the imine nitrogen atom in the presence of 25 equiv. AlMe(3) as activator at 20 °C. (13)C NMR analysis indicates the resultant polymers are linear and no evidence on branch was found.