Invited
Studying dynamics in host-guest systems and applying to MR imaging

The dynamic properties of supramolecular assemblies can be useful for studying their 3D structures, understanding their functions and applying them for wide range uses. However, quantitative data about the kinetic phenomena occurring within such assemblies is not readily available using standard analytical tools. The so-called GEST (guest exchange saturation transfer) method allows the quantitative analysis of dynamic exchange processes for various guests and multiple hosts demonstrating the generality of the approach for a wide range of supramolecular systems. The method can detect complex formation that cannot be observed using standard ¹H and ¹⁹F NMR spectroscopy and can amplify NMR signals of otherwise undetectable peaks. Fitting of the obtained experimental spectra using Bloch–McConnell simulations allows to determine exchange rates for a series of host-guest systems across a wide range k_ex values of few tens to more than 5000 s⁻¹. This approach could provide a better understanding of supramolecular assemblies and systems and could result in an interesting role for host-guest interactions in molecular MR Imaging.