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Pseudopolymorphism en tetradeca-2,6-O-methyl-beta-cyclodextrin: las estructuras cristalinas para dos nuevos
J J Stezowski1, W Parker, S Hilgenkamp
1Contribution from the Department of Chemistry, Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588-0304, USA.
Journal of the American Chemical Society
|July 18, 2001
Resumen
La tetradeca-2,6-O-metil-beta-ciclodextrina exhibe una inusual solubilidad térmica negativa. Las estructuras cristalinas revelan flexibilidad conformacional e hidratación dependiente de la temperatura en este derivado de la beta-ciclodextrina.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- La cristalografía es una técnica de cristalografía.
- Química de los carbohidratos Química de los carbohidratos
Sus antecedentes:
- Las beta-ciclodextrinas (beta-CD) son oligosacáridos cíclicos con una cavidad hidrofóbica.
- Las beta-ciclodextrinas metiladas son ampliamente utilizadas en diversas aplicaciones.
- La tetradeca-2,6-O-metil-beta-ciclodextrina (per-2,6-OMe-beta-CD) muestra un comportamiento de solubilidad único.
Objetivo del estudio:
- Para dilucidar las estructuras cristalinas de los hidratos per-2,6-OMe-beta-CD.
- Para investigar el impacto de la temperatura de cristalización en la estructura.
- Para entender la flexibilidad conformacional de per-2,6-OMe-beta-CD. para entender la flexibilidad conformacional de per-2,6-OMe-beta-CD. para entender la flexibilidad conformacional de per-2,6-OMe-beta-CD. para entender la flexibilidad conformacional de per-2,6-OMe-beta-CD. para entender la flexibilidad conformacional de per-2,6-OMe-beta-CD. para entender la flexibilidad conformacional de per-2,6-OMe-beta-CD. para entender la flexibilidad conformacional de per-2,6-OMe-beta-CD. para entender la flexibilidad conformacional de per-2,6-OMe-beta-CD.
Principales métodos:
- Difracción de rayos X de un solo cristal.
- Cristalización a temperaturas controladas (4°C y 50°C).
- Análisis estructural de las formas de hidrato.
Principales resultados:
- Se determinaron dos nuevas estructuras cristalinas de los hidratos de per-2,6-OMe-beta-CD: per-2,6-OMe-beta-CD·1.08H(2) O y per-2,6-OMe-beta-CD·14.7H(2) O. Se determinaron dos nuevas estructuras cristalinas de los hidratos de per-2,6-OMe-beta-CD·1.08H(2) O y de los hidratos de per-2,6-OMe-beta-CD·14.7H(2) O.
- La estructura cristalina de per-2,6-OMe-beta-CD·1.08H(2) O reveló una flexibilidad conformacional.
- Se observaron residuos de glucosa desordenados y una ocupación de moléculas de agua dependiente de la temperatura.
Conclusiones:
- Las estructuras cristalinas proporcionan información sobre el arreglo molecular de los hidratos per-2,6-OMe-beta-CD.
- La flexibilidad conformal es una característica clave de esta beta-ciclodextrina metilada.
- La temperatura influye significativamente en el nivel de hidratación y los detalles estructurales.
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