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<p>The efficient copolymerization of ethylene with polar monomer using Ti catalysts remains a challenge. This study presents a detailed density functional theory (DFT)-based investigation of the copolymerization mechanisms of α-olefins with polar monomers catalyzed by titanium complexes bearing [N, P] ligands. By analyzing key elementary steps-chain initiation, propagation, and termination-this work elucidates the electronic and steric effects of ligand substituents (-F, -CH<sub>3</sub>​) on catalytic activity and polymer molecular weight. Results demonstrate that electron-withdrawing substituents (-F) reduce energy barriers for ethylene homopolymerization by up to 8&#xa0;kcal/mol compared to -CH<sub>3​</sub>, enhancing polymerization rates. No significant decrease in energy barriers occurs with increasing fluorine atom count in ethylene/octene copolymerization. Computational analysis reveals that fluorinated titanium catalysts enable efficient ethylene/9-decen-1-ol copolymerization with minimal energy barrier increase compared to homopolymerization, facilitating the synthesis of ultra-high molecular weight polar olefin copolymers. The steric bulk of ligands significantly influences chain termination pathways, with bulky -F groups suppressing <i>β</i>-H elimination and increasing polymer molecular weight. These findings establish a predictive DFT model for designing high-performance catalysts for functional polyolefin synthesis.</p>

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DFT study of [N, P] Ti complexes-catalyzed ethylene-polar monomer copolymerization

  • 期刊论文

  • 发表日期：

    2025年10月14日

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  • Jiaojiao Zhang,
  • Wenwen Cong,
  • Yi Li

摘要

The efficient copolymerization of ethylene with polar monomer using Ti catalysts remains a challenge. This study presents a detailed density functional theory (DFT)-based investigation of the copolymerization mechanisms of α-olefins with polar monomers catalyzed by titanium complexes bearing [N, P] ligands. By analyzing key elementary steps-chain initiation, propagation, and termination-this work elucidates the electronic and steric effects of ligand substituents (-F, -CH3​) on catalytic activity and polymer molecular weight. Results demonstrate that electron-withdrawing substituents (-F) reduce energy barriers for ethylene homopolymerization by up to 8 kcal/mol compared to -CH3​, enhancing polymerization rates. No significant decrease in energy barriers occurs with increasing fluorine atom count in ethylene/octene copolymerization. Computational analysis reveals that fluorinated titanium catalysts enable efficient ethylene/9-decen-1-ol copolymerization with minimal energy barrier increase compared to homopolymerization, facilitating the synthesis of ultra-high molecular weight polar olefin copolymers. The steric bulk of ligands significantly influences chain termination pathways, with bulky -F groups suppressing β-H elimination and increasing polymer molecular weight. These findings establish a predictive DFT model for designing high-performance catalysts for functional polyolefin synthesis.