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| DOI | 10.1007/S10847-012-0153-5 | ||
| Año | 2013 | ||
| Tipo | artículo de investigación |
Citas Totales
Autores Afiliación Chile
Instituciones Chile
% Participación
Internacional
Autores
Afiliación Extranjera
Instituciones
Extranjeras
The main purpose of this work was to study the chiral recognition thermodynamics of inclusion complexes formed by flavanones and beta-cyclodextrins, and its relation with the inclusion geometries, through NMR experiments. By using the racemic mixtures of (+/-)-flavanone (FL) and (+/-)-2'-hydroxyflavanone (2'OHFL), diasteroisomeric complexes were formed employing beta-cyclodextrin (beta CD), (2-hydroxypropil)-beta-cyclodextrin (HP beta CD) and heptakis-(2,6-O-dimethyl)-beta-cyclodextrin (DM beta CD). H-1 NMR experiments of the complexes showed enantiodifferentiation for FL/beta CD, FL/HP beta CD, FL/DM beta CD, 2'OHFL/HP beta CD and 2'OHFL/DM beta CD complexes, so they were able to be studied by obtaining the stoichiometry (1:1 for each complex), association constants (Ka), Ka ratios, and thermodynamics (Delta H, Delta S and Delta G). The results show that Ka values decrease with increasing temperature and that Ka ratio values removed from 1 not always reflect better enantiodiscrimination by NMR. Thermodynamics (Delta H and Delta G) show an exothermic and spontaneous formation of the complexes. Since the results were established for each couple of diasteroisomeric complexes separately, comparison of thermodynamics between them was possible, concluding that one half of the couples of diasteroisomeric complexes present chiral recognition due to enthalpic phenomena and the other half due to entropic phenomena. Additionally, ROESY experiments were performed to estimate the inclusion geometry of the complexes, which are in good agreement with the thermodynamic and Ka results.
| Ord. | Autor | Género | Institución - País |
|---|---|---|---|
| 1 | ACUNA-ROUGIER, CRISTINA LUCIA | Mujer |
Universidad de Chile - Chile
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| 2 | OLEA-AZAR, CLAUDIO ALBERTO | Hombre |
Universidad de Chile - Chile
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