Zwitterionic Ni(<scp>ii</scp>) complexes bearing pyrazolyl-ether-imidazolium ligands: synthesis, structural characterization and use in ethylene oligomerization
作者:Ana H. D. P. S. Ulbrich、Jorge L. S. Milani、Thierry Roisnel、Jean-François Carpentier、Osvaldo L. Casagrande
DOI:10.1039/c5nj01538c
日期:——
activity in ethylene oligomerization [TOF = 2100–29300 (mol C2H4)·(mol Ni−1 h−1)] with good selectivities for 1-butene (80.4–89.8 wt% of total products), which vary according to the ligand environment. Under biphasic conditions, the Ni3/[Bmim]·[AlCl4]/toluene catalytic system proved to be active for ethylene oligomerization with a TOF of 10700 (mol C2H4)·(mol Ni−1 h−1) and highly selective towards production
一系列新的通式为NiCl 3(L)的四配位Ni(II)配合物(Ni1,L = 1-(2-(2-(2-甲基咪唑-乙氧基)乙基)-3,5-二甲基吡唑; Ni2,L = 1- (2-(1,2-二甲基咪唑-乙氧基)乙基)-吡唑; Ni3,L = 1-(2-(2-(1,2-二甲基咪唑-乙氧基)乙基)-3,5-二甲基吡唑; Ni4,L = 1-高产率地制备了(2-(2-正丁基咪唑并乙氧基)乙基)-3,5-二甲基吡唑。所有这些配合物均通过元素分析进行了表征,并对Ni1,Ni2和Ni3进行了X射线晶体学分析。在固态下,这些镍配合物是单体,吡唑基-醚-咪唑为单齿配体。咪唑鎓单元上的正电荷被与Ni(II)连接的第三氯离子提供的负电荷抵消,从而形成两性离子结构。在用甲基铝氧烷(MAO)或倍半氯化乙基铝(EASC)活化后,这些络合物在乙烯低聚[TOF = 2100–29 300(mol C 2 H 4)·(mol