The 2-(N-alkylcarboxamide)-6-iminopyridine ligands (L1–L7) can bind as either mono-anionic tridentate N⁁N⁁N ligands on reaction with PdCl2(CH3CN)2, to form complexes LPdCl (C1–C7), or as neutral tridentate N⁁N⁁O ligands with NiCl2·6H2O, to produce complexes LNiCl2 (C8–C14). All metal complexes were characterized by IR spectroscopy and elemental analysis, and in the case of the palladium complexes, by 1H and 13C NMR spectroscopy. The crystal structures of C3, C4, C6, C10, and C12 were determined by X-ray crystallography, and revealed a distorted square geometry around the palladium centre, whereas for nickel, a distorted square-pyramidal geometry was adopted. The representative palladium complex (C3) was further reacted with AgBF4 in acetonitrile affording the salt [L3Pd(CH3CN)][BF4] (C15) and the structure of this was confirmed by single-crystal X-ray diffraction. By contrast, carrying out the reaction in dichloromethane rather than acetonitrile, in the presence of malononitrile (CNCH2CN), resulted in the formation of the bimetallic palladium complex [L3Pd(CNCH2CN)PdL3]·2[BF4] (C16). Upon activation with diethylaluminium chloride, all the nickel complexes showed high activity for ethylene dimerization. Furthermore, the palladium complexes exhibited good activities in the vinyl-polymerization of norbornene upon activation with MAO.
2-(N- 烷基甲酰胺)-6-亚
氨基吡啶配体(L1-L7)在与 PdCl2(CH3CN)2、或中性三叉 N⁁N⁁O
配体与 NiCl2-6H2O 反应生成络合物 LNiCl2(C8-C14)。所有
金属配合物都通过红外光谱和元素分析进行了表征,
钯配合物则通过 1H 和 13C NMR 光谱进行了表征。通过 X 射线晶体学测定了 C3、C4、C6、C10 和 C12 的晶体结构,结果显示
钯中心周围呈扭曲的正方形几何结构,而
镍中心周围呈扭曲的正方锥形几何结构。具有代表性的
钯复合物(C3)在
乙腈中与
AgBF4 进一步反应,生成盐 [L3Pd(CH3CN)][BF4] (C15),其结构通过单晶 X 射线衍射得到证实。相比之下,在
二氯甲烷而不是
乙腈中进行反应,在
丙二腈(CNCH2CN)的存在下,会形成双
金属
钯复合物[L3Pd(CNCH2CN)PdL3]-2[BF4](C16)。在
二乙基氯化铝的活化作用下,所有
镍络合物都显示出很高的
乙烯二聚化活性。此外,
钯配合物在与 MAO 活化后,在
降冰片烯的
乙烯基聚合反应中也表现出良好的活性。