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Los marcos orgánicos covalentes 3D cristalizados selectivamente a través del diseño conformacional
Ha L Nguyen1,2, Cornelius Gropp1, Yanhang Ma3
1Department of Chemistry, University of California Berkeley; Kavli Energy Nanoscience Institute at UC Berkeley; and Berkeley Global Science Institute, Berkeley, California 94720, United States.
Journal of the American Chemical Society
|November 13, 2020
Resumen
Los investigadores diseñaron unidades de construcción triangulares y cuadradas para formar selectivamente marcos orgánicos covalentes de imina cristalina (COF) con una gran superficie. Este control de la conformación es clave para lograr la topología y las propiedades deseadas del material.
Área de la Ciencia:
- Ciencias de los materiales
- Química
- Nanotecnología
Sus antecedentes:
- Las estructuras orgánicas covalentes (COF) son polímeros porosos cristalinos con propiedades sintonizables.
- La síntesis selectiva de COF con topologías específicas y alta cristalinidad sigue siendo un desafío.
- El control de la conformación de las unidades de construcción es crucial para el montaje dirigido de la estructura.
Objetivo del estudio:
- Desarrollar una estrategia para la formación selectiva de COF de imina con la topología fjh.
- Investigar el papel de la conformación de la unidad de construcción en la cristalización de COF.
- Síntesis y caracterización de nuevos COF con grandes superficies.
Principales métodos:
- Diseño conformal de las unidades de construcción triangulares (TTFB) y cuadradas (ETTA).
- Reticulación de las unidades diseñadas para formar COFs.
- Caracterización mediante técnicas de difracción espectroscópica, microscópica y de rayos X.
- Análisis de la porosidad y de la superficie mediante el método BET.
Principales resultados:
- Se logró la formación selectiva de una imina cristalina COF, COF-790, con la topología fjh.
- El COF-790 exhibe una alta superficie de Brunauer-Emmett-Teller (BET) de 2650 m2 g-1.
- Las conformaciones prediseñadas de las unidades de construcción (ángulos diédricos de 75-90°) fueron críticas para la formación de productos cristalinos.
- Se sintetizaron dos COF isoreticulares (COF-791 y COF-792) utilizando unidades cuadradas alternativas.
Conclusiones:
- El control conformal de las unidades de construcción es una estrategia poderosa para la síntesis selectiva de COF.
- El método desarrollado permite el diseño racional de COF cristalinos con topologías específicas.
- Los COF sintetizados poseen una alta porosidad y superficie, lo que indica aplicaciones potenciales en el almacenamiento y la separación de gases.
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