Highly Active and Thermally Robust Nickel Enolate Catalysts for the Synthesis of Ethylene‐Acrylate Copolymers

Abstract The insertion copolymerization of polar olefins and ethylene remains a significant challenge in part due to catalysts′ low activity and poor thermal stability. Herein we demonstrate a strategy toward addressing these obstacles through ligand design. Neutral nickel phosphine enolate catalysts with large phosphine substituents reaching the axial positions of Ni achieve activity of up to 7.7×10 3 kg mol −1 h −1 (efficiency >35×10 3 g copolymer/g Ni) at 110 °C, notable for ethylene/acrylate copolymerization. NMR analysis of resulting copolymers reveals highly linear microstructures with main‐chain ester functionality. Structure‐performance studies indicate a strong correlation between axial steric hindrance and catalyst performance.