α-Diimine Nickel Catalyst with Remote Rigid Spatial Hindrance for the Synthesis of Polyolefin Elastomers

Recently, it has been discovered that α-diimine nickel catalysts have potential in the preparation of polyolefin elastomers using ethylene as the only raw material. By adjusting the steric hindrance and electronic effect of ligands, the performance of the catalysts can be regulated, resulting in the generation of polyethylene with different properties. In this study, we have designed and characterized a series of α-diimine ligands with remote rigid steric hindrance and placed functional groups with different electronic effects to more accurately regulate the performance of the catalyst. The obtained catalysts owed high activity and high thermal stability, could catalyzed ethylene polymerization to obtain polyethylene elastomers with adjustable parameters (molecular weight, branch density, and melt point) and properties, and had the ability to catalyze ethylene copolymerized with polar monomer. The preparation of these catalysts provides new alternative catalysts for the development of polyolefin elastomers.