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Pilar[5]areno como un co-factor en la creación de plantillas para la formación de rotaxano
Chenfeng Ke1, Nathan L Strutt, Hao Li
1Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Journal of the American Chemical Society
|September 25, 2013
Resumen
Este estudio muestra cómo los macrociclos pillar[5]areno y cucurbit[6]urilo modelan cooperativamente las cicloadiciones azida-alquina, formando rotaxanos complejos con altos rendimientos. Esta plantilla cooperativa permite una síntesis eficiente de nuevas arquitecturas moleculares.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- Síntesis orgánica La síntesis orgánica.
- Química Macrocíclica La Química Macrocíclica es la química macrocíclica en la que se encuentran las moléculas.
Sus antecedentes:
- Las enzimas utilizan coenzimas para la unión al sustrato en los sitios activos.
- Los macrociclos como el pilar[5]areno y el cucurbito[6]urilo pueden modelar las reacciones químicas.
- Cucurbit[6]uril por sí solo no constituye una plantilla para ciertas cicloadiciones azida-alquina.
Objetivo del estudio:
- Para investigar el efecto de templación cooperativa del pilar[5]areno y el cucurbito[6]uril en las cicloadiciones azida-alquina.
- Para sintetizar nuevas estructuras de rotaxano utilizando esta plantilla cooperativa.
- Para explorar el papel del enlace de hidrógeno entre los macrociclos en el proceso de templación.
Principales métodos:
- Templación cooperativa de dications de bipyridinium con cadenas de azidoalquilo que varían utilizando el pilar[5]areno y cucurbit[6]uril.
- Reconocimiento ortogonal y enlace de hidrógeno entre los macrociclos para dirigir la formación de rotaxano.
- Optimización de la reacción a 55 °C en acetonitrilo para una síntesis rápida y de alto rendimiento.
Principales resultados:
- Formación de dos [4]rotaxanos y un [5]rotaxano con un rendimiento >90% en 2 horas.
- Atrapar con éxito los isómeros conformacionales del pilar[5]areno en los componentes de las mancuernas de rotaxano.
- Aislamiento de un [5]rotaxano que contiene dos pilares[5]anillos de areno con simetría C5.
- Extensión del alcance constitucional para la regioquímica en 1,3-dipolar cicloadiciones.
Conclusiones:
- El pilar[5]areno y el cucurbito[6]urilo exhiben una cooperatividad positiva en la creación de plantillas de cicloadiciones azida-alquina.
- Este efecto cooperativo conduce a una síntesis eficiente y ecológica de rotaxanos complejos.
- El sistema demuestra el reconocimiento ortogonal y la templación en condiciones suaves.
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