Teaching indicators to unravel the kinetic features of host–guest inclusion complexes

Abstract

Both thermodynamic and kinetic insights are needed for a proper analysis of association and dissociation processes of host-guest interactions. However, kinetic descriptions of supramolecular sys-tems are scarce in the literature...

Simultaneous analyte indicator binding assay (SBA) for the monitoring of reversible host–guest complexation kinetics

“…The data derived for norcamphor and (+)fenchone show excellent agreement with our previously published values measured by kinGDA and kinIDA. 28 The studies on alicyclic ketonesCB7 and organic ammoniumCB6 complexations confirm the applicability of kinSBA method for the measurement of and covering a range of several 𝑘 𝐻𝐺 𝑖𝑛 𝑘 𝐻𝐺 𝑜𝑢𝑡 orders of magnitude (Table 1). Importantly, the kinSBA method can be applied for direct determinations of equilibrium constants of host-guest binding defined as 𝐾 𝐻𝐺 = / .…”

“…We recently introduced the kinetic indicator displacement assay (kinIDA) and kinetic guest displacement assay (kinGDA) that allow for probing the temporal characteristics of hostguest inclusion complexes of nonchromophoric or nonluminescent guests. 28 One drawback of these competitivebinding methods is the need to independently determine the binding affinity a priori, e.g. by titration experiments, in order to allow for a reliable fitting of the kinetic ingression and egression rates.…”

“…guest (kinGDA) or dye (kinIDA) can potentially lead to complications in the kinetic mechanism, e.g., if ternary host-dye-guest complexes are formed as transient species. 28 The aim of the present study was to develop an alternative accurate procedure whose signal shape provides immediate qualitative insight into the relationship among the rate constants of the reversible binding of the guest and indicator molecules. Fig.…”

Elucidating dissociation activation energies in host–guest assemblies featuring fast exchange dynamics

“…However, in all cases the low emission signal change upon binding and the very fast guest inclusion kinetics prevented the extraction of any meaningful data with this established protocol. Likewise, even with the newly introduced kinetic versions of the indicator- and guest-displacement assays ( kin GDA and kin IDA) that are applicable also to non-chromophoric guest, 59 we did not succeed in fitting reliable rate constants for these fast equilibrating guests (Fig. S3–S5 † ).…”

Photoresponsive Binding Dynamics in High‐Affinity Cucurbit[8]uril‐Dithienylethene Host‐Guest Complexes

“…Pioneering works on the kinetics of CBn‐based host‐guest complexes have already disclosed important mechanistic details about their binding dynamics and the structural, electronic and external factors that affect the complexation rates [16–33] . Of special interest for the design of stimuli‐responsive systems are the studies demonstrating that the complexation kinetics can be controlled by protonation/deprotonation of the guest molecules [23,28,34–37] .…”