Three nickel(II) complexes (C1–C3) bearing diamine-bridged 4-hydroxysalicylaldehyde ligands (L1–L3) were successfully synthesized, and all the compounds were characterized by physicochemical and spectroscopic methods. The influence of the oligomerization parameters on the catalytic properties of complex C2 was systematically investigated. The results showed that oligomerization parameters played an important role in the catalytic properties and the catalytic activity was 19.90 × 10⁴ g/(mol·Ni·h) and the selectivity of C₈₊ olefins was 60.25% when the precatalyst dosage was 5 μmol, the Al/Ni molar ratio was 500, the temperature was 25 °C, the reaction time was 30 min and the pressure of ethylene was 0.7 MPa. Complexes C1–C3 with different lengths of the bridged group were evaluated for ethylene oligomerization, and the results showed that the length of the alkyl chain in the ligand had little influence on the catalytic properties. Complex C4 based on ethanediamine-bridged salicylaldimine and C5 based on the hyperbranched salicylaldimine in our previous work were also investigated to study the influence of the ligand structure on the catalytic properties. The catalytic activity [31.80 × 10⁴ g/(mol·Ni·h)] and the content of the low-carbon oligomers (70.16%) for complex C4 were higher than complex C2 with hydroxyl substituent in benzene ring. The catalytic activity and the content of the low carbon oligomers for complex C5 were far higher than other four complexes.

成功合成了三个带有二胺桥联的4-羟基水杨醛配体（L1 - L3）的镍（II）配合物（C1 - C3），并通过物理化学和光谱法对所有化合物进行了表征。系统研究了低聚参数对复合物C2催化性能的影响。结果表明，低聚参数在催化性能中起着重要作用，催化活性为19.90×10 ⁴  g /（mol·Ni·h）和C ₈₊的选择性。当预催化剂剂量为5μmol，Al / Ni摩尔比为500，温度为25℃，反应时间为30分钟且乙烯的压力为0.7MPa时，烯烃为60.25％。评价了具有不同桥联基团长度的配合物C1 - C3的乙烯低聚反应，结果表明，配体中烷基链的长度对催化性能的影响很小。在我们以前的工作中，还研究了基于乙二胺桥联的水杨醛亚胺的配合物C4和基于超支化水杨醛亚胺的C5，以研究配体结构对催化性能的影响。催化活性[31.80×10 ⁴ g /（mol·Ni·h）]和配合物C4的低碳低聚物的含量（70.16％）高于苯环中带有羟基取代基的配合物C2。配合物C5的催化活性和低碳低聚物的含量远高于其他四种配合物。