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Formación de cápsulas, intercambio de carboxilatos y exploración DFT de clúster de metallocavitandos de cadmio:
Peter D Frischmann1, Glenn A Facey, Phuong Y Ghi
1Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
Journal of the American Chemical Society
|March 4, 2010
Resumen
Los investigadores desarrollaron nuevos grupos de carboxilato de cadmio dentro de los macrociclos de base de Schiff. Estos metallocavitandos forman cápsulas con propiedades únicas de huésped-huésped, útiles para diseñar nuevos materiales supramoleculares.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- Coordinación Química de la Coordinación
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- Los macrociclos de base de Schiff sirven como plantillas para la formación de grupos metálicos.
- Los metalocavitandos ofrecen propiedades únicas de huésped-invitado y capacidades de ensamblaje supramolecular.
Objetivo del estudio:
- Para sintetizar y caracterizar una nueva familia de grupos de carboxilato de heptacadmio modelados por los macrociclos de base de Schiff.
- Para investigar las interacciones huésped-huésped, el comportamiento supramolecular y las propiedades dinámicas de estos complejos de metallocavitand.
Principales métodos:
- Solución de temperatura variable y espectroscopia de RMN en estado sólido.
- Difracción de rayos X de un solo cristal (SCXRD)
- Teoría funcional de la densidad (DFT) cálculos.
- Estudios termodinámicos y cinéticos.
- Espectroscopia de RMN en estado sólido (2) H.
Principales resultados:
- Agrupaciones aisladas de carboxilato de heptacadmio con plantilla dentro de los [3 + 3] macrociclos de base Schiff.
- Los metallocavitands adoptan estructuras en forma de cuenco, formando cápsulas a través de la dimerización con sitios accesibles para los huéspedes.
- Coeficiente de embalaje alto (0.80) para la N,N-dimetilformamida (DMF) encapsulada debido a las fuertes interacciones huésped-huésped.
- La dimerización es un proceso impulsado por la entropía con un paso común que determina la velocidad para el intercambio de ligandos y la dimerización.
- Se observó una rotación de 3 veces de moléculas de DMF encapsuladas utilizando espectroscopia de RMN en estado sólido (2) H.
Conclusiones:
- El estudio proporciona una comprensión completa de las propiedades anfitrión-invitado y dinámicas de una nueva clase de metallocavitandos.
- Estos hallazgos pueden guiar el diseño de nuevos catalizadores supramoleculares y materiales funcionales.
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