A series of novel 2,6-bis(imino)pyridyl iron catalysts: synthesis, characterization and ethylene oligomerization
摘要:
A series of novel 2.6-bis(imino)pyridyl iron complexes {2,6-(2-X-4-Y-5-ZC(6)H(2)N=CCH3)(2)C5H3N}FeCl2 (X=Cl, Y=CH3, Z=H (2); X=Br.Y=CH3, Z=H(3);X=F,Y=H,Z=CH3 (4);X=Cl, Y=H,Z=CH3 (5); X=Cl, Y=F (7)) have been synthesized and characterized with elemental analysis and IR. These iron coordinative complexes, activated with methylaluminoxane (MAO), lead to highly active ethylene oligomerization (> 10(7) g/mol Fe h) and the products are mostly linear alpha-olefins (> 90%). The catalytic activities and product properties depend on the substituents on aryl rings and the reaction conditions. As reaction temperature increases, the catalytic activities decrease rapidly and more low-molar-mass products are produced. The product distributions are almost independent of the Al/Fe molar ratio, but the catalytic activities change in different trends when the ortho-substituents on the aryl rings are different. The other three complexes have also been synthesized for comparison to investigate the steric hindrance and electronic effect on the properties of complexes. The complex with adaptable steric hindrance and electronic properties exhibits the highest catalytic activities. (c) 2004 Elsevier B.V. All rights reserved.
Catalytic ethylene oligomerization on cobalt(II) bis(imino)pyridine complexes bearing electron-withdrawing groups
作者:Artem A. Antonov、Nina V. Semikolenova、Evgenii P. Talsi、Konstantin P. Bryliakov
DOI:10.1016/j.jorganchem.2019.02.002
日期:2019.3
A series of novel bis(imino)pyridinecobalt(II) chlorides, LCoCl2, with the bis(imino)pyridine ligands bearing one or several electron-withdrawing substituents (F, Cl, Br, CF3) at the aniline moieties, have been prepared and characterized. In the presence of methylalumoxane (MAO), these complexes have demonstrated high ethylene oligo- and polymerization activity (up to 1.8·107 g products∙(mol Co)−1 h−1 bar−1)
一系列新颖的双(亚氨基)吡啶钴(II)氯化物LCoCl 2具有在苯胺部分带有一个或多个吸电子取代基(F,Cl,Br,CF 3)的双(亚氨基)吡啶配体准备和表征。在甲基铝氧烷(MAO)的存在下,这些配合物表现出高的乙烯低聚和聚合活性(高达1.8·10 7 g产品∙(mol Co)-1 h -1 bar -1),提供的产品范围为1-丁烯和Z,E -2-丁烯至严格线性低分子量(M n 〜300…700)聚乙烯。讨论了反应结果对配体结构的依赖性。