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Towards a Real Knotaxane

Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany
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Chemistry 2020, 2(2), 305-321; https://doi.org/10.3390/chemistry2020020
Received: 12 March 2020 / Revised: 8 April 2020 / Accepted: 10 April 2020 / Published: 26 April 2020
Two classes of mechanically interlocked molecules, [3]rotaxanes and knotted [1]rotaxanes, were the subject of this investigation. The necessary building blocks, alkyne-terminated axles containing two ammonium ions and azide-terminated stoppers, and azide-containing substituted macrocycles, have been synthesized and characterized. Different [3]rotaxanes were synthesized by copper-catalyzed “click” reactions between the azide stoppers and [3]pseudorotaxanes formed from the dialkyne axles and crown ethers (DB24C8). Methylation of the triazoles formed by the “click” reaction introduced a second binding site, and switching via deprotonation/protonation was investigated. In preliminary tests for the synthesis of a knotted [1]rotaxane, pseudorotaxanes were formed from azide-containing substituted macrocycles and dialkyne substituted diammonium axles, and copper-catalyzed “click” reactions were carried out. Mass spectral analyses showed successful double “click” reactions between two modified macrocycles and one axle. Whether a knotted [1]rotaxane was formed could not be determined. View Full-Text
Keywords: mechanically interlocked molecules; knot; rotaxane; macrocycle; click reaction; switching; shuttle mechanically interlocked molecules; knot; rotaxane; macrocycle; click reaction; switching; shuttle
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Duden, T.; Lüning, U. Towards a Real Knotaxane. Chemistry 2020, 2, 305-321.

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