Molecular Necklaces Formed Through Zn2+‐Templated Binding of Macrocycles with Dynamically Formed Imines as Guest Recognition Sites

• Published in: Chemistry : a European journal Vol. 30; no. 54; pp. e202402404 - n/a
• Main Authors: Wu, Yi‐Ju, Liu, Yi‐Hung, Chiu, Sheng‐Hsien
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 25.09.2024
• Subjects: Aldehydes; Assembling; Assembly; catenanes; Diamines; dynamic covalent bonds; Imines; Ions; molecular necklaces; Protonation; Recognition; Rotaxanes; Zinc
• ISSN: 0947-6539; 1521-3765; 1521-3765
• DOI: 10.1002/chem.202402404

Herein we demonstrate an “in‐ring establishing” strategy for assembling interlocked molecules through dynamic imine formation, “establishing” the host recognition sites in situ. Using Zn2+ ions to template the assembly of a pyridine‐containing macrocycle with semidumbbell‐shaped triazole‐containing aldehyde and amine derivatives, we obtained the corresponding [2]rotaxane in high yield (85 %) after subsequent imine reduction (NaBH4) and amine protonation (NH4PF6). We performed the same three steps (assembly, reduction, protonation) to prepare a stable and highly symmetrical [5]molecular necklace ([5]MN) from 12 components (two almost‐90°‐oriented dialdehydes, two almost‐90°‐oriented diamines, four macrocycles, four Zn2+ ions) in an overall yield of 69 %. An “in‐ring establishing” strategy has afforded a molecular necklace from two almost‐90°‐oriented dialdehydes, two almost‐90°‐oriented diamines, four macrocycles, and four Zn2+ ions, in an overall yield of 69 % over three steps (assembly, imine reduction, and amine protonation).