Morota Yudai, Suzuki Takanaga, Landenberger Kira B
Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo Ward Kyoto 615-8510 Japan
RSC Adv. 2022 Jan 20;12(5):2641-2651. doi: 10.1039/d1ra06957h. eCollection 2022 Jan 18.
Halogen bonding is rapidly becoming recognized as a viable and useful intermolecular interaction in supramolecular chemistry. While various monomers amenable to radical polymerization methods containing halogen bonding donors have been developed, this study aims to expand the type of monomers that incorporate this intermolecular interaction to facilitate use of cationic polymerization by developing three novel vinyl ether monomers containing halogen bonding donor moieties: 2,3,5,6-tetrafluoro-4-iodophenoxyethyl vinyl ether (C2I), 2,3,5,6-tetrafluoro-4-iodophenoxybutyl vinyl ether (C4I), and 2-(2,3,5,6-tetrafluoro-4-iodophenoxyethoxy)ethyl vinyl ether (O3I). Well controlled cationic polymerization is achievable through the use of a proton trap, 2,6-di--butylpyridine. The use of SnCl as a co-Lewis acid was found to accelerate the reaction. Between the three monomers, the difference in the chain length is shown to influence the reaction rate, with the longest chain demonstrating the fastest polymerization. Initial studies of the halogen bonding ability shows that halogen bonding exists for all three monomers but is most pronounced in C4I. The polymerized vinyl ethers also exhibit halogen bonding. Due to the ease of synthesis and polymerization, these are promising new monomers to increase functionality available for polymers synthesized using cationic polymerization.
卤键作为超分子化学中一种可行且有用的分子间相互作用，正迅速得到认可。虽然已经开发出了各种适用于自由基聚合方法的含卤键供体的单体，但本研究旨在通过开发三种含卤键供体部分的新型乙烯基醚单体，来扩展包含这种分子间相互作用的单体类型，以促进阳离子聚合反应的应用：2,3,5,6 - 四氟 - 4 - 碘苯氧基乙基乙烯基醚（C2I）、2,3,5,6 - 四氟 - 4 - 碘苯氧基丁基乙烯基醚（C4I）和2 - (2,3,5,6 - 四氟 - 4 - 碘苯氧基乙氧基)乙基乙烯基醚（O3I）。通过使用质子捕获剂2,6 - 二叔丁基吡啶，可以实现良好控制的阳离子聚合反应。发现使用SnCl作为共路易斯酸可以加速反应。在这三种单体之间，链长的差异显示出对反应速率有影响，最长链的单体表现出最快的聚合反应。对卤键能力的初步研究表明，这三种单体都存在卤键，但在C4I中最为明显。聚合后的乙烯基醚也表现出卤键。由于合成和聚合反应都很容易，这些是很有前景的新型单体，可增加使用阳离子聚合反应合成的聚合物的可用功能。
