Lee Gue Seon, Lee Hyo Won, Lee Hyun Sub, Do Taeyang, Do Jean-Louis, Lim Jeewoo, Peterson Gregory I, Friščić Tomislav, Kim Jeung Gon
Department of Chemistry and Research Institute of Physics and Chemistry, Jeonbuk National University Jeonju 54896 Republic of Korea
Department of Chemistry, McGill University 801 Sherbrooke Street West H3A0B8 Montreal Canada
Chem Sci. 2022 Sep 7;13(39):11496-11505. doi: 10.1039/d2sc02536a. eCollection 2022 Oct 12.
Ruthenium-alkylidene initiated ring-opening metathesis polymerization has been realized under solid-state conditions by employing a mechanochemical ball milling method. This method promotes greenness and broadens the scope to include mechano-exclusive products. The carbene- and pyridine-based Grubbs 3-generation complex outperformed other catalysts and maintained similar mechanistic features of solution-phase reactions. High-speed ball milling provides sufficient mixing and energy to the solid reaction mixture, which is composed of an initiator and monomers, to minimize or eliminate the use of solvents. Therefore, the solubility and miscibility of monomers and Ru-initiators are not limiting factors in solid-state ball milling. A wide variety of solid monomers, including ionomers, fluorous monomers, and macromonomers, were successfully polymerized under ball milling conditions. Importantly, direct copolymerization of immiscible (ionic/hydrophobic) monomers exemplifies the synthesis of mechano-exclusive polymers that are difficult to make using traditional solution procedures. Finally, the addition of a small amount of a liquid additive (, liquid-assisted grinding) minimized chain-degradation, enabling high-molecular-weight polymer synthesis.
通过机械化学球磨法，在固态条件下实现了钌亚烷基引发的开环易位聚合反应。该方法提高了绿色环保性，并拓宽了范围，将机械化学专有产物纳入其中。基于卡宾和吡啶的第三代格拉布催化剂表现优于其他催化剂，并保持了与溶液相反应相似的机理特征。高速球磨为由引发剂和单体组成的固体反应混合物提供了充分的混合和能量，从而最大限度地减少或消除了溶剂的使用。因此，单体和钌引发剂的溶解性和混溶性在固态球磨中并非限制因素。在球磨条件下，包括离聚物、含氟单体和大分子单体在内的多种固体单体均成功实现了聚合。重要的是，不相容（离子型/疏水性）单体的直接共聚体现了机械化学专有聚合物的合成，而使用传统溶液法很难制备此类聚合物。最后，添加少量液体添加剂（即液体辅助研磨）可将链降解降至最低，从而实现高分子量聚合物的合成。
