Homochiral π‐Rich Covalent Organic Frameworks Enabled Chirality Imprinting in Conjugated Polymers: Confined Polymerization and Chiral Memory from Scratch

• Published in: Angewandte Chemie International Edition 2024-05, Vol.63 (22), p.e202403878-n/a
• Main Authors: Zhang, Xiaofeng, Chen, Xinfa, Fu, Shiguo, Cao, Ziping, Gong, Wei, Liu, Yan, Cui, Yong
• Format: Article
• Language: English
• Subjects: Amino acids; chiral memory; Chirality; chirality Imprinting; conjugated polymers; covalent organic framework; enantioselective separation; Helices; Optical activity; Polymerase chain reaction; Polymerization; Polymers
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202403878

Optically active π‐conjugated polymers (OACPs) have garnered increasing research interest for their resemblance to biological helices and intriguing chirality‐related functions. Traditional methods for synthesizing involve decorating achiral conjugated polymer architectures with enantiopure side substituents through complex organic synthesis. Here, we report a new approach: the templated synthesis of unsubstituted OACPs via supramolecularly confined polymerizations of achiral monomers within nanopores of 2D or 3D chiral covalent organic frameworks (CCOFs). We show that the chiral π‐rich nanospaces facilitate the in situ enantiospecific polymerization and self‐propagation, akin to nonenzymatic polymerase chain reaction (PCR) system, resulting in chiral imprinting. The stacked polymer chains are kinetically inert enough to memorize the chiral information after liberating from CCOFs, and even after treatment at temperature up to 200 °C. The isolated OACPs demonstrate robust enantiodiscrimination, achieving up to 85 % ee in separating racemic amino acids. This underscores the potential of utilizing CCOFs as templates for supramolecularly imprinting optical activity into CPs, paving the way for synthetic evolution and advanced functional exploration of OACPs. Optically active π‐conjugated polymers (OACPs) were synthesized through confined polymerization within π‐rich homochiral covalent organic frameworks, utilizing a chiral imprinting process. The isolated OACPs retained chirality and displayed robust enantiodiscrimination, achieving up to 85 % ee in separating racemic amino acids.