A Constrained Structural Symmetry Strategy for Nickel-Catalyzed Olefin Polymerization and Copolymerization with Polar Monomers

Conventional strategies for enhancing performance in α-diimine nickel-catalyzed olefin polymerization have predominantly focused on modulating steric hindrance and electronic properties. While effective in suppressing β-hydride elimination and increasing molecular weight, these approaches often lead to reduced incorporation of polar monomers in copolymerization reactions. Herein, we report a constrained structural symmetry strategy through the design of an oxa-macrocyclic α-diimine nickel catalyst, which enforces a specific spatial arrangement of the dibenzhydryl substituents on the same side of the N–Ni–N plane. Compared with the simulant catalyst bearing dibenzyl bulky groups on the opposite side, the topologically constrained catalyst exhibits higher activity (>10 7 g·mol –1 ·h –1 ), produces polymer with a higher molecular weight, and also achieves enhanced polar monomer incorporation (up to 5.3 mol %) in copolymerization. These results underscore the unique role of structural symmetry manipulation in breaking the conventional trade-off between molecular weight control and polar comonomer incorporation, offering a new paradigm for designing high-performance olefin polymerization catalysts. Furthermore, the cyclic ether moiety can serve as an anchor to immobilize the catalyst on Lewis acid-modified silica. This heterogenization leads to increased polymer molecular weight, reduced branching density, and improved control over product morphology.