Inclusion Complexes of Naphthols with Cyclodextrins in Aqueous Solution. A 1H-NMR Study
Abstract
The inclusion complexes of a and 3 naphthols with α, β and γ cyclodextrin in aqueous (D2O) solution (pD11) were studied by high field (300 MHz) 1H-NMR spectroscopy. Values for the association constants, calculated from complexation induced shifts according to a modification of the Benesi- Hildebrand equation, indicate that the strenght of the complexation increases in the order γ CD>β CD>α CD, and is of the same order of magnitude for α and β naphthol. The inclusion induces widely different chemical shifts changes in protons of the naphthols, suggesting different orientations and extents of penetration of the guests in the macrocycles. Especially variable shifts of protons close to the phenol group suggest a different involvement of this group in local interactions with the cyclodextrins.
Keywords
Inclusion Complex Association Constant Local Interaction Variable Shift Hildebrand EquationPreview
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