A series of neutral nickel complexes featuring N-fluorinated phenyl salicylaldiminato chelate ligands was synthesized, and the novel molecular structure of complex C14 was further confirmed by X-ray crystallographic analysis. The neutral nickel complexes showed high activity up to 9.96×105 g oligomers/(mol Ni·h) and high selectivity of C6 in catalyzing ethylene oligomerization using methylaluminoxane (MAO) as cocatalyst. It was observed that the strong electron-withdrawing effect of the fluorinated salicylaldiminato ligand was able to significantly increase the catalytic activity for oligomerization of ethylene. In addition, the influence of reaction parameters such as Al/Ni molar ratio, reaction temperature, a variety of cocatalyst and ethylene pressure on catalytic activity was investigated. [ABSTRACT FROM AUTHOR]