By taking advantage of electronic influence of ligand design, the novel neutral nickel complexes bearing strong electron-donating N-acylated imidazolin-2-imine ligand were synthesized and characterized. The nickel catalysts conducted ethylene polymerization with high activity and good thermal stability, affording semicrystalline polyethylene with short chain branches (32-46/1000 C atoms). The complex Ni2 bearing adamantyl substituent on the imidazoline ligand showed higher activity than phenyl substituted complex Ni1, and highest activity was observed at 60 degrees C (up to similar to 10(6) g.mol(-1).h(-1)). Most importantly, the catalysts were also effective for the copolymerization of ethylene and 5-hexenyl acetate with moderate activity (similar to 10(5) g.mol(-1).h(-1)). The microstructure analyses by the C-13 NMR spectroscopy indicated that the 5-hexenyl acetate was successfully incorporated into the polyethylene main chain with reasonable comonomer content. (C) 2020 Elsevier Inc. All rights reserved.