Increasing the thermal stability of α-diimine nickel (II) catalyst by camphorquinone as a great backbone and investigating the steric effects of this backbone in ethylene polymerization

In the α-diimine catalyst system, catalyst design with high thermal stability through ligand modifications is very challenging. This paper reports the preparation of three camphyl-based ligands with diverse steric effect and their Ni (II) complexes. To evaluate the backbone and ligand steric effects these nickel complexes were used as catalysts in the polymerization of ethylene. The camphyl-based catalysts show high thermal stability with good catalyst activity up to 75 °C. In ethylene polymerization using bulky isopropyl substitution in the ortho position of the aniline moieties, it is achievable to tune the catalytic activities (6 × 10 5 g/mol Ni.h), polymer molecular weights (16 × 10 4 g/mol), and polymer melting temperatures (to 117.5 °C) over an extensive range.