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La unión divalente de un calix[4]areno funcionalizado con bis ((adamantilo) a anfitriones basados en
Alart Mulder1, Tommaso Auletta, Andrea Sartori
1Laboratory of Supramolecular Chemistry & Technology, MESA Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands.
Journal of the American Chemical Society
|May 27, 2004
Resumen
La unión de un calix[4]areno funcionalizado con bis ((adamantilo) a los dímeros de beta-ciclodextrina es significativamente más fuerte en las superficies de oro que en la solución. Esta diferencia se explica por un modelo teórico centrado en los efectos efectivos de la concentración.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- Química entre anfitrión y huésped.
- Química de las superficies.
Sus antecedentes:
- Las arenas de calix[4] y las ciclodextrinas (CDs) son moléculas de huésped bien establecidas.
- Los dimeros de calix[4]areno (1) y beta-ciclodextrina (CD) atados a EDTA (2) están diseñados para las interacciones huésped-huésped.
- Comprender las afinidades de unión en diferentes entornos es crucial para las aplicaciones de reconocimiento molecular.
Objetivo del estudio:
- Para cuantificar y comparar la afinidad de unión divalente de calix[4]areno 1 a CD dimero 2 en solución frente a las monocapas autoensambladas (SAM) en oro.
- Desarrollar y aplicar un modelo teórico para racionalizar las diferencias observadas en las constantes vinculantes.
- Para aclarar los factores que contribuyen a una mayor unión a las superficies.
Principales métodos:
- Estudios de vinculación basados en soluciones para determinar la constante de asociación para la interacción entre 1 y 2.
- Resonancia de plasma de superficie (SPR) o técnicas similares para medir la unión de 1 a CD SAM en el oro.
- Desarrollo de un modelo teórico que interprete la unión divalente como sucesos monovalentes secuenciales.
Principales resultados:
- La constante de unión en solución (1.2 x 10^7 M^-1) fue tres órdenes de magnitud más débil que en CD SAMs sobre oro (aprox. 10^10 M^-1). es decir, 10^10 M^-1). es decir, 10^10 M^-1.
- Un modelo teórico logró racionalizar con éxito los datos de enlace considerando dos eventos de enlace monovalente consecutivos.
- El modelo destacó el papel significativo de un término de "concentración efectiva" para la unión intramolecular en superficies.
Conclusiones:
- La unión divalente anfitrión-invitado se mejora significativamente en las superficies en comparación con la solución.
- La mayor unión a las superficies se atribuye principalmente a una mayor concentración efectiva debido al movimiento molecular restringido.
- El marco teórico proporciona una herramienta valiosa para comprender y predecir afinidades de unión en diversos sistemas supramoleculares.
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