Song Qilei, Qiu Hong, Liu Lijun, Zhang Guangzhao, Peruch Frédéric, Carlotti Stéphane, Zhao Junpeng
Faculty of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China.
Bordeaux INP, Univ. Bordeaux CNRS, LCPO, UMR 5629, 33600, Pessac, France.
Angew Chem Int Ed Engl. 2023 Apr 24;62(18):e202300187. doi: 10.1002/anie.202300187. Epub 2023 Mar 24.
One-step sequence-selective block copolymerization requires stringent catalytic control of monomers relative activity and enchainment order. It has been especially rare for A B -type block copolymers from simple binary monomer mixtures. Here, ethylene oxide (EO) and N-sulfonyl aziridine (Az) compose a valid pair provided with a bicomponent metal-free catalyst. Optimal Lewis acid/base ratio allows the two monomers to strictly block-copolymerize in a reverse order (EO-first) as compared with the conventional anionic route (Az-first). Livingness of the copolymerization facilitates one-pot synthesis of multiblock copolymers by addition of mixed monomers in batches. Calculation results reveal that a Janus effect of Lewis acid on the two monomers is key to enlarge the activity difference and reverse the enchainment order.
一步法序列选择性嵌段共聚需要对单体的相对活性和链增长顺序进行严格的催化控制。对于由简单二元单体混合物制备的AB型嵌段共聚物来说，这种情况尤其罕见。在这里，环氧乙烷（EO）和N-磺酰基氮丙啶（Az）在双组分无金属催化剂的作用下构成了一个有效的组合。与传统的阴离子路线（先加Az）相比，最佳的路易斯酸/碱比例使得这两种单体能够严格地以相反的顺序（先加EO）进行嵌段共聚。共聚反应的活性使得通过分批加入混合单体能够一锅法合成多嵌段共聚物。计算结果表明，路易斯酸对这两种单体的“两面神效应”是扩大活性差异并逆转链增长顺序的关键。
