ISSN:
0749-1581
Keywords:
Lanthanide-induced NMR shifts
;
1H NMR
;
Host-guest complex
;
γ-Cyclodextrin-paramagnetic anion complex
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The host-guest complex formed in aqueous solution between γ-cyclodextrin (γ-CD) and the macrocyclic paramagnetic shift reagent TmDOTP5- was examined by NMR spectroscopy. Paramagnetic lanthanide-induced shifts (LIS) and spin-lattice relaxation rate enhancements in the proton resonances of γ-CD on binding of TmDOTP5- were used to define the position of the guest anion within the host cavity. A proportionality constant which relates pseudo-contact shifts induced by TmDOTP5- to the geometrical position of each ligand nucleus (previously determined from a LIS study of the TmDOTP5- complex) was used to determine a fully bound LIS value for each γ-CD proton. These values, in combination with experimental LIS data from TmDOTP5- titrations at constant γ-CD concentration, were then used to obtain the association constant for the host-guest complex (3.9-4.5 mol l-1). These constants were indicative of a weak host-guest interaction and consistent with the location of the TmDOTP5- binding site reported by the LIS values well above the center of the γ-CD cavity.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260320610
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