Enhancing Suppression of Chain Transfer via Installing Bulky N‐ortho‐Aryl Substituents into α‐Diimine Nickel System

Abstract

Recently, the important role of sterically bulky aromatic substituents at the axial position of the metal center for synthesizing high‐performance catalysts were recognized. In this study, a series of α‐diimine nickel complexes with bulky N‐ortho‐aryl substituents were designed and synthesized. The as‐synthesized nickel complexes showed high activities (up to 2.3×107 g·mol‐1·h‐1) and superior thermostability, giving access to moderately branched polyethylenes (35‐86/1000C) with high molecular weights (up to 197.5×104 g·mol‐1). The polyethylene materials generated by these nickel complexes at 80 °C exhibited outstanding tensile mechanical. In addition, these nickel complexes could also catalyze the copolymerization of ethylene and polar monomer with modest activity (such as undecenoic acid, 10‐undecen‐1‐ol and 6‐chlorohex‐1‐ene), yielding functionalized polyolefin with adjustable molecular weights (6.8‐222.9×104 g·mol‐1) and incorporation ratios (0.2‐4.3 mol%).