南开大学崔春明团队报道了硼氧基钛配合物在烯烃催化共聚中的高极性单体含量。相关研究成果发表在2024年8月27日出版的《德国应用化学》。

制备极性单体含量高（超过20mol%）的聚烯烃长期以来一直是一个挑战。

该文中，研究人员设计并合成了含大体积供电子N-杂环硼氧基配体的半茂钛（Cp′）[HC（Ar）N]₂BOTiCl₂。由Cp*和大体积硼氧基配体负载的配合物（Cp*）[HC（Ar）N]₂BOTiCl₂（2，Ar=2,6-iPr2C6H3；5，Ar=2,4,6-Me3C6H2）已被证明，能有效催化乙烯与长链α-烯烃的共聚反应。

特别是，预催化剂5能够以前所未有的高极性单体含量（高达32.1mol%）受控合成聚（乙烯-co-9-癸烯-1-醇），同时保持高催化活性。结构分析和DFT计算表明，大体积强供电子的硼氧基配体可以有效稳定阳离子活性物种。对羟基官能化共聚物的力学研究表明，由于聚合物网络中存在氢键，其表现出高强度和韧性。

附：英文原文

Title: Boryloxy Titanium Complex-Enabled High Polar Monomer Contents in Catalytic Copolymerization of Olefins

Author: Chuanzhi Wei, Lulu Guo, Cheng Zhu, Chunming Cui

Issue&Volume: 2024-08-27

Abstract: The preparation of polyolefins with high polar monomer contents (above 20 mol %) has long been a challenge. Half-titanocenes (Cp′)[HC(Ar)N]2BOTiCl2 bearing bulky electron-donating N-heterocyclic boryloxy ligands have been designed and synthesized. The complexes (Cp*)[HC(Ar)N]2BOTiCl2 (2, Ar = 2,6-iPr2C6H3; 5, Ar = 2,4,6-Me3C6H2) supported by Cp* and the bulky boryloxy ligands have been shown to efficiently catalyze the copolymerization of ethylene with long chain α-olefins. In particular, precatalyst 5 enabled the controlled synthesis of poly(ethylene-co-9-decen-1-ol) with unprecedented high polar monomer contents up to 32.1 mol% while maintaining high catalytic activity. The structural analysis and DFT calculations disclosed that the bulky and strong electron-donating boryloxy ligands could effectively stabilize cationic active species. The mechanical studies on the hydroxyl-functionalized copolymers disclosed that they exhibited high strength and toughness because of the existence of hydrogen bonds in the polymer network.

DOI: 10.1002/anie.202414464

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202414464