One‐Pot Precision Synthesis of AB, ABA and ABC Block Copolymers via Switchable Catalysis

• Published in: Angewandte Chemie 2022-03, Vol.134 (12), p.n/a
• Main Authors: Yang, Zhenjie, Hu, Chenyang, Cui, Fengchao, Pang, Xuan, Huang, Yuezhou, Zhou, Yanchuan, Chen, Xuesi
• Format: Article
• Language: English
• Subjects: Abscisic acid; Block copolymers; Carbon dioxide; Catalysis; Catalysts; Chemistry; Chemoselectivity; CO2 Insertion; Copolymerization; Copolymers; Cycle ratio; Epoxides; Macromolecules; Monomers; Multi-Block Copolymer; Salen-Manganese Complex; Switchable Catalysis
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202117533

The switchable catalysis using a commercial salenMn catalyst was firstly developed and applied in the one‐pot selective copolymerization from anhydrides, epoxides, CO2 and ϵ‐caprolactone (ϵ‐CL) mixtures for the precise synthesis of AB, ABA and novel ABC block copolymers. The observed unique double switch process comprising three different polymerization cycles was rationalized by theoretical calculations. Surprisingly, the first block turned out to be an efficient macromolecular initiator for the consecutive introduction of carbonate linkages into copolymers, albeit with dominant cyclization with the catalyst alone. Further, through the selective reaction on different epoxides, the switchable copolymerization of up to five monomers was achieved yielding well‐defined multi‐block copolymers with structural diversity and functionality. The precise synthesis of well‐defined block copolymers with molecular complexity by simple techniques has always been a meaningful but rarely achieved task. Here, a commercial switchable catalysis is reported comprising a delicate “double switch” process. This unique switch can be applied up to pentacomponent mixtures to prepare sequence‐controlled AB, ABA, and ABC copolymers.