Investigating the electron-withdrawing effect of aryl substituents in the catalytic behavior of α-diimine nickel (II) catalyst on ethylene polymerization

In the α-diimine-based catalytic systems, it is highly challenging to increase the thermal stability of the catalyst through ligand modifications. In this work, we are interested in conducting an investigation on the polymerization of ethylene catalyzed by α-diimine Ni(II) complexes with camphyl backbone and electron-withdrawing substituents in aryl positions. The synthesis and characterization of camphyl-based α-diimine ligands were described and confirmed by 1HNMR, 13CNMR, H-H COSY, FT-IR, and elemental analysis. Far-IR and EDS confirmed the formation of the Ni(II) complexes. The synthesized complexes were active in ethylene polymerization with activities on the level of 104 g of PE (mol of Ni.h)-1. The electron-withdrawing substituent catalyst exhibited high activity in ethylene polymerization.