Noncovalent Interactions in Late Transition Metal-Catalyzed Polymerization of Olefins

Macromolecules, Journal Year: 2024, Volume and Issue: 57(15), P. 6899 - 6913

Published: July 23, 2024

Language: Английский

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Stable Ultrahighly Branched Polyethylene Synthesis via Externally Robust Chain-Walking Polymerization

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(17), P. 13531 - 13541

Published: Aug. 27, 2024

Recently, late-transition-metal-catalyzed chain-walking polymerization has emerged as a promising method for synthesizing range of polyethylenes, including linear, branched, and hyperbranched structures, solely from ethylene feedstock. The spatial configuration the catalyst is crucial factor in determining branching patterns observed resulting polyethylene. In this study, we designed employed series stereoscopically bulky α-diimine Ni(II) Pd(II) complexes featuring axial flexible cycloalkyl substituents an equatorial rigid dibenzobarrelene backbone (co)polymerization. These exhibited high catalytic activity, reaching up to 106 g/(mol Ni·h), yielded very-high-molecular-weight polyethylene with extremely narrow molecular weight distributions (1.00–1.27) very densities (105–153/1000C) living behavior under various temperatures. Most interestingly, density cyclohexyl-substituted complex almost independent conditions ultrahighly branched ultrahigh (up 1097 kg/mol) can be accessed. On other hand, corresponding also demonstrated moderate achieving 105 Pd·h), highly weights ranging 160.8 511.9 kg/mol. Moreover, these were capable generating high-molecular-weight E-MA copolymers adjustable incorporation ratios (0.85–2.77 mol %) (106–117/1000C). Through comparative analysis single-crystal structures DFT calculations, found that create interesting ligand environment favors chain walking over propagation nickel-catalyzed system. This finding provides valuable insights into design more efficient controllable catalysts synthesis polyethylenes tailored properties.

Language: Английский

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Hemilabile α‐Diimine Nickel Catalyzed Olefin Polymerization

Chinese Journal of Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 10, 2024

Comprehensive Summary For coordination‐insertion olefin polymerization, the development of novel transition‐metal catalysts has drawn extensive attention in this field. In contribution, we designed a series hemilabile α‐diimine nickel bearing oxygen atom as neighboring group. The steric hindrance and number these complexes ( Ni1—Ni4 ) could be adjusted, which influenced ethylene (co)polymerization processes. introduction atoms enhance thermal stability during polymerization for Ni2 compared to counterpart without atoms. And copolymerization process with polar monomers, higher catalytic activity (1.4 × 10 6 g·mol −1 ·h monomer incorporation ratio (1.2 mol%) were achieved. However, Ni4 four work was not active due interaction between center. effect presented an example polymerization.

Language: Английский

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Synthesis of Linear Low-Density Polyethylene Waxes Through Chain-Walking Benzocycloalkyl Nickel-Catalyzed Ethylene Polymerization

Journal of Organometallic Chemistry, Journal Year: 2024, Volume and Issue: 1021, P. 123373 - 123373

Published: Sept. 7, 2024

Language: Английский

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