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Se está endureciendo: síntesis de catenanos y rotaxanos con plantilla de cobalto (III)

David A Leigh¹, Paul J Lusby, Roy T McBurney

¹School of Chemistry, University of Edinburgh, The King's Buildings, West Mains Road, Edinburgh EH9 3JJ, United Kingdom. David.Leigh@ed.ac.uk

Journal of the American Chemical Society

|March 12, 2009

Resumen

Los iones de cobalto (III) son el patrón de la síntesis de moléculas mecánicamente entrelazadas como los catenanos y los rotaxanos. La metátesis de olefinas de cierre de anillo crea estas arquitecturas complejas, que pueden desmetalizarse para producir estructuras neutras enlazadas con hidrógeno.

Área de la Ciencia:

Química supramolecular de las moléculas.
Síntesis orgánica La síntesis orgánica.
Coordinación Química de la Coordinación

Sus antecedentes:

La síntesis dirigida por plantillas es crucial para la construcción de arquitecturas moleculares complejas.
Los iones de metal de transición ofrecen plataformas versátiles para organizar ligandos y dirigir el autoensamblaje.
Los catenanos y rotaxanos representan clases clave de moléculas mecánicamente entrelazadas con propiedades únicas.

Objetivo del estudio:

Para reportar la síntesis de catenanos y rotaxanos utilizando una plantilla de cobalto (III).
Para explorar el uso de piridina-2,6-dicarboxamido ligandos con grupos terminales de alqueno para la macrociclización.
Investigar la formación de arquitecturas mecánicamente entrelazadas a través de la metátesis de olefinas de cierre de anillo.

Principales métodos:

Coordinación de los ligantes tridentados dianiónicos de piridina-2,6-dicarboxamido con el cobalto (III).
Metátesis de olefinas de cierre de anillo para formar estructuras macrocíclicas.
Cristalografía de rayos X para elucidación estructural de complejos y moléculas libres de metales.
Desmetallación reductiva para obtener catenanos y rotaxanos neutros.

Principales resultados:

Se sintetizó un complejo de "figura de ocho" no interconectado con un rendimiento del 42%.
Se obtuvo un catenato isomérico [2] con un rendimiento del 69%, confirmado por cristalografía de rayos X.
A [2]rotaxano se ensambló en el 61% de rendimiento utilizando la plantilla de cobalto.
La desmetallación produjo catenanos y rotaxanos neutros con coconformaciones estables.

Conclusiones:

El cobalto (III) sirve como una plantilla eficaz para la síntesis de catenanos y rotaxanos.
La metátesis de olefinas de cierre de anillo es una estrategia viable para construir estas moléculas mecánicamente entrelazadas.
Las estructuras entrelazadas resultantes pueden desmetalizarse para formar compuestos neutros estabilizados por enlaces de hidrógeno.

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