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Dinámica de los enlaces en vidrios de marco metálico-orgánico
Alexander E Khudozhitkov1, Naoki Ogiwara2,3, Masaki Donoshita2,4
1Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia.
Journal of the American Chemical Society
|May 2, 2024
Resumen
La vitrificación de los vidrios de marco metálico-orgánico (MOF) ZIF-62 tiene un impacto en la dinámica del vinculante. Mientras que los movimientos rápidos persisten, la vitrificación facilita movimientos cooperativos más lentos, reduciendo las barreras de activación y manteniendo la porosidad.
Área de la Ciencia:
- Ciencias de los materiales
- Química del estado sólido
- Espectroscopia
Sus antecedentes:
- Los vidrios de marco metálico-orgánico (MOF) son nuevos materiales híbridos con dinámicas microscópicas poco claras.
- La comprensión de la movilidad del enlace en las gafas MOF es crucial para su aplicación.
- Los estudios anteriores se centraron en el comportamiento reológico macroscópico, dejando sin explorar la dinámica microscópica.
Objetivo del estudio:
- Investigar el efecto de la vitrificación en la dinámica del enlace en ZIF-62.
- Para aclarar la movilidad microscópica de los enlaces en las gafas ZIF-62.
- Para comparar la dinámica de enlace en cristalino y vidrio ZIF-62.
Principales métodos:
- Se empleó la espectroscopia de resonancia magnética nuclear (RMN) en estado sólido.
- El análisis de relajación de RMN se utilizó para sondear la movilidad del enlace.
- Se utilizaron simulaciones de dinámica molecular para la verificación.
Principales resultados:
- La RMN H reveló libraciones restringidas locales y giros de gran amplitud de los enlaces ZIF-62.
- La vitrificación no alteró significativamente los movimientos rápidos y individuales de volteo del enlace.
- La vitrificación facilitó movimientos de torsión lentos y cooperativos al disminuir la barrera de activación.
Conclusiones:
- El ZIF-62 de vidrio conserva una porosidad permanente, consistente con los hallazgos anteriores.
- El trastorno de corto alcance en la alineación de ligandos surge de la distorsión del ángulo de coordinación en las gafas.
- La dinámica microscópica, en particular la movilidad del enlace, está significativamente influenciada por el proceso de vitrificación.
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