Nickel catalysts with asymmetric steric hindrance for ethylene polymerization

α-Diimide catalysts have attracted widespread attention due to their unique chain walking characteristics. A series of α-diimide nickel/palladium catalysts with different electronic effects and steric hindrances were designed and synthesized for olefin polymerization. In this work, we synthesized a series of asymmetric α-diimide nickel complexes with different steric hindrances and used them for ethylene polymerization. These nickel catalysts have high ethylene polymerization activity, up to 6.51×10⁶ g·mol⁻¹·h⁻¹, and the prepared polyethylene has a moderate melting point and high molecular weight (up to 38.2 × 10⁴ g·mol⁻¹), with a branching density distribution between 7 and 94 branches per 1000 carbons. More importantly, the polyethylene prepared by these catalysts exhibits excellent tensile properties, with strain and stress reaching 800% and 30 MPa, respectively.