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Estructuras de difracción de rayos X monocristalinas de estructuras orgánicas covalentes

Tianqiong Ma^1,2, Eugene A Kapustin³, Shawn X Yin⁴

¹State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, China.

Science (New York, N.Y.)

|July 7, 2018

Resumen

Los investigadores desarrollaron un método para hacer crecer grandes cristales únicos de marcos orgánicos covalentes porosos (COF). Este avance permite un análisis estructural preciso a nivel atómico, superando las limitaciones anteriores en la caracterización de COF.

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Área de la Ciencia:

Química de los materiales
La cristalografía
Química supramolecular

Sus antecedentes:

La cristalización sigue siendo un desafío significativo en la química de los marcos orgánicos covalentes porosos (COF).
La caracterización estructural de los COF se ha limitado principalmente al modelado y al análisis de datos de difracción, que carece de precisión atómica.

Objetivo del estudio:

Desarrollar un procedimiento general para el cultivo de grandes cristales únicos de COF tridimensionales basados en iminas.
Permitir la determinación estructural de las COF en alta resolución mediante difracción de rayos X monocristalino.

Principales métodos:

Desarrolló un procedimiento general para el crecimiento monocristalino de COF basados en imina.
Se utilizó la difracción de rayos X monocristalino para recopilar datos de alta resolución (hasta una resolución de 0,83 angstroms).
Solución de estructura inequívoca y refinamiento anisotrópico preciso.

Principales resultados:

Creció con éxito grandes cristales individuales de COF-300, su forma hidratada, COF-303, LZU-79 y LZU-111.
Logró una precisión atómica en el descifrado de las características estructurales, incluyendo la interpenetración, la disposición de las moléculas invitadas y el desorden de los enlaces.
Identificamos topologías poco comunes y una conectividad inminente inversa con detalles sin precedentes.

Conclusiones:

El método desarrollado supera el desafío de la cristalización en la química de COF.
La difracción de rayos X de un solo cristal proporciona conocimientos estructurales definitivos anteriormente inalcanzables.
Permite una comprensión precisa de las estructuras de COF para el diseño de materiales avanzados.