美国德克萨斯农工大学Michaudel Quentin研究团队报道了立体控制无环二烯复分解聚合。相关研究成果发表在2022年10月24日出版的《自然—化学》。

烯烃的顺/反几何结构会显著影响聚烯烃的热性能和机械性能。然而，有效控制这一参数的聚合方法却很少。

该文中，研究人员报道了利用二硫代钌卡宾与顺式单体结合的反应性的立体保持性无环二烯易位聚合的进展。这些钌催化剂表现出良好的顺式几何结构保持性，并耐受许多极性官能团，从而能够合成所有顺式聚酯、聚碳酸酯、聚醚和聚亚硫酸盐。立体保持型无环二烯易位聚合的特点还在于催化剂负载量低，对单体批次中的反式杂质具有耐受性，这将有助于大规模实施。

反应温度和时间的调节会导致立体保留的侵蚀，从而能够以可预测的顺反比进行立体控制的聚烯烃合成。差示扫描量热法和热重分析，清楚地证明了重复烯烃的立体化学对热性能的影响。

附：英文原文

Title: Stereocontrolled acyclic diene metathesis polymerization

Author: Hsu, Ting-Wei, Kempel, Samuel J., Felix Thayne, Alyssa P., Michaudel, Quentin

Issue&Volume: 2022-10-24

Abstract: The cis/trans geometry of olefins is known to dramatically influence the thermal and mechanical properties of polyalkenamers. Yet, polymerization methods that efficiently control this parameter are scarce. Here we report the development of a stereoretentive acyclic diene metathesis polymerization that uses the reactivity of dithiolate Ru carbenes combined with cis monomers. These Ru catalysts exhibit exquisite retention of the cis geometry and tolerate many polar functional groups, enabling the synthesis of all-cis polyesters, polycarbonates, polyethers and polysulfites. The stereoretentive acyclic diene metathesis polymerization is also characterized by low catalyst loadings and tolerance towards trans impurities in the monomer batch, which should facilitate large-scale implementation. Modulation of the reaction temperature and time leads to an erosion of stereoretention, permitting a stereocontrolled synthesis of polyalkenamers with predictable cis:trans ratios. The impact of the stereochemistry of the repeating alkenes on the thermal properties is clearly demonstrated through differential scanning calorimetry and thermogravimetric analysis.

DOI: 10.1038/s41557-022-01060-6

Source: https://www.nature.com/articles/s41557-022-01060-6