Quantifying Guest Exchange in Supramolecular Systems

• Published in: Angewandte Chemie 2017-11, Vol.129 (48), p.15516-15520
• Main Authors: Avram, Liat, Wishard, Anthony D., Gibb, Bruce C., Bar‐Shir, Amnon
• Format: Article
• Language: English
• Subjects: Assemblies; Austauschraten; Chemistry; Foreign exchange rates; GEST; NMR; NMR-Spektroskopie; Nuclear magnetic resonance; Saturation; Supramolekulare Chemie; Wirt-Gast-Systeme
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.201708726

The ability to accurately determine and quantitatively evaluate kinetic phenomena associated with supramolecular assemblies, in real time, is key to a better understanding of their defined architectures and diverse functionalities. Therefore, analytical tools that can precisely assess a wide range of exchange rates within such systems are of considerable importance. This study demonstrates the ability to use an NMR approach based on saturation transfer for the determination of rates of guest exchange from molecular capsules. By using cavitands that assemble into distinct dimeric assemblies, we show that this approach, which we term guest exchange saturation transfer (GEST), allows the use of a conventional NMR setup to study and quantitatively assess a wide range of exchange rates, from 35 to more than 5000 s−1. Heimliche Gäste: Gastaustauschsättigungstransfer (GEST), ein NMR‐basierter Ansatz zur Untersuchung von dynamischen supramolekularen Aggegaten, ermöglichte die quantitative Bestimmung von Austauschprozessen in dimeren Kapseln – auch dann, wenn 1H‐ oder 19F‐NMR keine Hinweise auf eine Komplexbildung erbracht hatten. Durch Verwendung verschiedener Gäste konnte eine Bandbreite an Austauschraten von 35 bis über 5000 s−1 ermittelt werden.