Search results for "Host-guest complexe"
showing 9 items of 19 documents
Binding properties of heptakis-(2,6-di-O-methyl)-β-cyclodextrin and mono-(3,6-anhydro)-β-cyclodextrin: a polarimetric study
2011
The binding constants for the inclusion complexes formed between heptakis-(2,6-di-O-methyl)-β-cyclodextrin (MβCD) and mono-(3,6-anhydro)-β-cyclodextrin (AβCD) with a set of suitably selected organic guests, were measured by means of polarimetry. Measurements were carried out at various pH values in order to ensure the correct protonation state for ionizable guests. Experimental data suggest that the binding properties of MβCD may be rationalized considering the less polar and more hydrophobic character of the cavity, although similar variations in conformational/dynamic behaviour occur as for native βCD. On the other hand, AβCD shows some similarities with αCD, due to the significant distor…
Binding equilibria between beta-cyclodextrin and p-nitro-aniline derivatives: the first systematic study in mixed water-methanol solvent systems.
2009
Abstract Complexation equilibria, in mixed water–methanol solvent media, between native β-cyclodextrin and a set of suitably selected p -nitro-aniline derivatives were studied by means of polarimetry. The effects exerted by the organic co-solvent on the conditional inclusion free energies Δ G cond 0 and the differential molar optical rotations Δ Θ were thoroughly analyzed under the perspective of the enthalpy–entropy compensation effect. Experimental data suggest an intimate participation (‘dynamic co-inclusion’) of solvent molecules in the formation and in the conformational dynamics of the host–guest inclusion complex.
Binding properties of mono-(6-deoxy-6-amino)-β-cyclodextrin towards p-nitroaniline derivatives: a polarimetric study
2009
Abstract Polarimetry was used in order to investigate the formation of supramolecular complexes between mono-6-amino-β-cyclodextrin and various p-nitroaniline derivatives at two different pH values. Comparison with the behaviour of native β-cyclodextrin gave us the opportunity to consider the effect exerted by the presence of charged groups, having different solvation requirements, on the binding equilibrium. Data offer some support to the hypothesis of ‘dynamic co-inclusion’ of solvent molecules within the host–guest complex.
Recognition of N-Alkyl- and N-Aryl-Acetamides by N-Alkyl Ammonium Resorcinarene Chlorides
2014
N-alkyl ammonium resorcinarene chlorides are stabilized by an intricate array of intra- and intermolecular hydrogen bonds that leads to cavitand-like structures. Depending on the upper-rim substituents, self-inclusion was observed in solution and in the solid state. The self-inclusion can be disrupted at higher temperatures, whereas in the presence of small guests the self-included dimers spontaneously reorganize to 1:1 host-guest complexes. These host compounds show an interesting ability to bind a series of N-alkyl acetamide guests through intermolecular hydrogen bonds involving the carbonyl oxygen (C=O) atoms and the amide (NH) groups of the guests, the chloride anions (Cl(-)) and ammoni…