Quantitative self-assembly of a purely organic three-dimensional catenane in water

• Published in: Nature chemistry Vol. 7; no. 12; pp. 1003 - 1008
• Main Authors: Li, Hao, Zhang, Huacheng, Lammer, Aaron D., Wang, Ming, Li, Xiaopeng, Lynch, Vincent M., Sessler, Jonathan L.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-12-2015; Nature Publishing Group
• Subjects: 140/131; 140/58; 639/638/403/932; 639/638/541/966; Analytical Chemistry; Anthracenes - chemistry; Biochemistry; Chemistry; Chemistry/Food Science; Chromatography, Reverse-Phase; Crystallography; Crystallography, X-Ray; Inorganic Chemistry; Liquid chromatography; Magnetic Resonance Spectroscopy; Mass spectrometry; Models, Molecular; Organic Chemistry; Physical Chemistry; Water - chemistry
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/nchem.2392

Self-assembly by means of coordinative bond formation has opened up opportunities for the high-yield synthesis of molecules with complex topologies. However, the preparation of purely covalent molecular architectures in aqueous media has remained a challenging task. Here, we present the preparation of a three-dimensional catenane through a self-assembly process that relies on the formation of dynamic hydrazone linkages in an acidic aqueous medium. The quantitative synthesis process and the mechanically interlocked structure of the resulting catenane were established by NMR spectroscopy, mass spectrometry, X-ray crystallography and HPLC studies. In addition, the labile hydrazone linkages of the individual [2]catenane components may be ‘locked’ by increasing the pH of the solution, yielding a relatively kinetically stable molecule. The present study thus details a simple approach to the creation and control of complex molecular architectures under reaction conditions that mimic biological milieux.
Purely organic molecules with complex interlocked architectures have proved difficult to prepare in water. Now, a three-dimensional organic [2]catenane has been obtained in a weakly acidic aqueous solution, through an almost quantitative self-assembly process relying on dynamic hydrazone linkages. The catenane is kinetically stable in neutral and weakly basic environments.