Synthesis, characterization and ethylene oligomerization of nickel complexes bearing N-(2-(1H-benzo[d]imidazol-2-yl)quinolin-8-yl)benzamide derivatives
作者:Kefeng Wang、Miao Shen、Wen-Hua Sun
DOI:10.1039/b822441b
日期:——
A series of N-(2-(1-R-1H-benzo[d]imidazol-2-yl)quinolin-8-yl)-2-R1-4-R2-benzamide derivatives (5–12) was synthesized and characterized. These compounds 5–11 (5: R = H, R1 = H, R2 = H; 6: R = H, R1 = Cl, R2 = H; 7:R = H, R1 = H, R2 = Cl; 8: R = H, R1 = H, R2 = Br; 9: R = Me, R1 = H, R2 = H; 10: R = Et, R1 = H, R2 = H; 11: R = iPr, R1 = H, R2 = H.) were treated with KOH, and then reacted with Ni(Ac)2·4H2O to form their nickel complexes (5a-11a), however, the dimethylated compound 12 reacted with NiCl2·6H2O to give complex 14a. Further investigation confirmed that compound 12 hydrolysized into a new compound N-methyl-2-(1-methyl-1H-benzo[d]imidazol-2-yl)quinolin-8-amine 14, and alternative synthesis confirmed the formation mechanism of 14a. All nickel complexes were characterized by elemental and spectroscopic analyses, and molecular structures of the representative compounds (12, 5a and 14a) were determined by the single-crystal X-ray diffraction. These Ni(II) complexes exhibited good to high activities up to 7.6 × 106g mol−1(Ni) h−1 in ethylene oligomerization upon activation with Et2AlCl. The reaction conditions and the nature of ligands affected on the catalytic performances of nickel complexes.
合成并表征了一系列 N-(2-(1-R-1H-苯并[d]咪唑-2-基)喹啉-8-基)-2-R1-4-R2-苯甲酰胺衍生物(5-12)。这些化合物 5-11(5: R = H, R1 = H, R2 = H; 6: R = H, R1 = Cl, R2 = H; 7:R = H, R1 = H, R2 = Cl; 8: R = H, R1 = H, R2 = Br; 9: R = Me, R1 = H, R2 = H; 10: R = Et, R1 = H, R2 = H; 11: R = iPr, R1 = H, R2 = H。然而,二甲基化合物 12 与 NiCl2-6H2O 反应生成了络合物 14a。进一步研究证实,化合物 12 会水解成新的化合物 N-甲基-2-(1-甲基-1H-苯并[d]咪唑-2-基)喹啉-8-胺 14,替代合成证实了 14a 的形成机理。所有镍络合物都通过元素分析和光谱分析进行了表征,代表性化合物(12、5a 和 14a)的分子结构通过单晶 X 射线衍射进行了测定。这些镍(II)配合物在与 Et2AlCl 活化时,在乙烯低聚过程中表现出良好到较高的活性,最高可达 7.6 × 106g mol-1(Ni) h-1。反应条件和配体性质对镍配合物的催化性能有影响。