Xiong Shuoyan, Hong Alexandria, Bailey Brad C, Spinney Heather A, Senecal Todd D, Bailey Hannah, Agapie Theodor
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Chemical Science, Core R&D, The Dow Chemical Company, Midland, MI 48667, USA.
Angew Chem Int Ed Engl. 2022 Aug 26;61(35):e202206637. doi: 10.1002/anie.202206637. Epub 2022 Jul 18.
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 kg mol h (efficiency >35×10 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.
极性烯烃与乙烯的插入共聚仍然是一个重大挑战，部分原因是催化剂活性低且热稳定性差。在此，我们展示了一种通过配体设计来克服这些障碍的策略。具有大膦取代基并延伸至镍轴向位置的中性镍膦烯醇盐催化剂，在110°C下实现了高达7.7×10 kg mol⁻¹ h⁻¹的活性（效率>35×10³ g共聚物/g镍），这对于乙烯/丙烯酸酯共聚而言十分显著。对所得共聚物的核磁共振分析揭示了具有主链酯官能团的高度线性微观结构。结构-性能研究表明轴向空间位阻与催化剂性能之间存在很强的相关性。
