Change of the kinetics of inclusion in cucurbit[7]uril upon hydrogenation and methylation of palmatine

Abstract

The negative activation entropy of tetrahydropalmatine inclusion makes the entry into cucurbit[7]uril significantly slower than in the case of dehydrocorydaline.

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

“…In comparison, dissociation activation energies of the uorescent guest berberine and other uorescent alkaloids are much larger, i.e. E a,out > 65 AE 1 kJ mol À1 , 58 as was determined by direct binding assays. Neither faster equilibrating guests for CB7 with lower E a,out barriers nor non-chromophoric guests can be investigated by established stopped-ow-coupled direct binding assays.…”

Encapsulation of Metronidazole in Biocompatible Macrocycles and Structural Characterization of Its Nano Spray-Dried Nanostructured Composite

“…The acidity diminution upon embedment in CB7 originates from the stabilization of the MetH + form by cation–dipole interactions with the partial negative charge of the carbonyl-laced portals of the macrocycle. Host–guest binding induced proton release suppression was also found for various dyes, drugs and ammonium compounds [ 25 , 26 , 27 , 28 , 29 ].…”

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

“…2) were selected as fluorescent indicators for the macrocyclic host cucurbit [7]uril (CB7) in this study as the half-life of their CB7 complexes varies more than 200-fold in the conveniently measurable time range. 14,29 Moreover, these indicators strongly emit when bound in the host cavity but have negligible fluorescence in water, thus providing large signal changes. In addition, the environmentsensitive stilbazolium-type dye DSMI was selected to examine the confinement effects on the rate constants of host-guest complexes for the smaller macrocycle, cucurbit [6]uril (CB6).…”

“…Please do not adjust margins the numerical solution of the system of differential equations characterizing the inclusion kinetics (S4-S8 in the ESI) taking the rate constants of complexation and dissociation ( (𝑘 𝐻𝐷 𝑖𝑛 ) of D as fixed input parameters as they can be 𝑘 𝐻𝐷 𝑜𝑢𝑡 ) determined from independent experiments by mixing H and D solutions. 29 The rate constants of ingression and (𝑘 𝐻𝐺 𝑖𝑛 ) egression ( of the guest G can then be determined by a 𝑘 𝐻𝐺 𝑜𝑢𝑡 ) least-square fitting routine. The so obtained experimental ingression and egression rates are summarized in Table 1.…”