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Influencia de los aniones en las estructuras supramoleculares de plata: características estructurales y propiedades
Irene Bassanetti1, Francesco Mezzadri, Angiolina Comotti
1Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Università degli Studi di Parma, Italy.
Journal of the American Chemical Society
|May 24, 2012
Resumen
Este estudio detalla la creación de estructuras metálicas orgánicas estables y porosas a partir de plata y un ligando específico. Estas estructuras forman hexámeres cíclicos que se autoensamblan en arquitecturas 3D con porosidad ajustable para la absorción de gases.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- Coordinación Química de la Coordinación
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- Los ligandos preorganizados ofrecen vías controladas de autoensamblaje.
- Los iones de plata ((I) son nodos versátiles para la construcción de complejas arquitecturas supramoleculares.
- El autoensamblaje jerárquico es clave para diseñar materiales porosos funcionales.
Objetivo del estudio:
- Sintetizar y caracterizar nuevas estructuras supramoleculares utilizando un ligando de bis ((pyrazolyl) metano funcionalizado con tioéter y precursores de plata.
- Investigar la organización jerárquica de estas estructuras desde hexámeres cíclicos discretos hasta marcos 3D.
- Para explorar la porosidad y las propiedades de absorción de gas de las estructuras metal-orgánicas resultantes.
Principales métodos:
- Reacciones de complejación entre el ligando (L) y los precursores de plata.
- Difracción de rayos X (cristal único y polvo) para la determinación estructural.
- Análisis de sorción de gases (CO2, CH4, adsorción de vapor) para evaluar la porosidad.
Principales resultados:
- Formación de hexámeros cíclicos orgánicos metálicos toroidales y estables ([AgL]6(X)6) en solución.
- El autoensamblaje jerárquico en arquitecturas cristalinas 3D con diferentes grupos espaciales (Fd3, R3) dependiendo del contraanión (PF6-, BF4-, CF3SO3-, NO3-).
- Generación de estructuras porosas con cavidades platónicas de forma sólida, que exhiben porosidad permanente y absorción reversible de gas / vapor después de la evacuación del disolvente.
Conclusiones:
- El ligando diseñado permite la formación de estructuras supramoleculares robustas y organizadas jerárquicamente con plata.
- El anión dicta la simetría y dimensionalidad de los marcos 3D resultantes.
- Estos marcos metal-orgánicos demuestran potencial como sorbentes selectivos para gases como el CO2 y el CH4.
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