Conformational changes of non-covalent complexes are of fundamental importance to many chemical and biological processes. Yet, these low-energy structural changes are usually fast and difficult to monitor, which poses challenges in their detailed kinetic understanding. Described in this work is the kinetics and thermodynamics correlation of the conformational change of a model supramolecular system featuring a flexible naphthocage and quaternary ammonium guests. Guest binding initially locks the host in two major conformations, which then equilibrates over time to the more stable conformer. The overall rate of the system to attain conformational equilibrium is found to inversely correlate to the thermodynamic stability of the host-guest complexes, and hence not only the kinetic parameters of the conformational exchange can be predicted from the easily obtainable thermodynamic data, but also the kinetic profile can be rationalized by the structural properties of the different guests.

This article is Open Access

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