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Cuadros orgánicos covalentes porosos cristalinos expandidos verticalmente

Shuailei Xie1,2, Matthew A Addicoat3, Donglin Jiang1,2

  • 1Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City 350207, China.

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Los investigadores crearon nuevos marcos orgánicos covalentes (COF) expandidos verticalmente mediante el uso de enlaces de coordinación. Estos COF expandidos abren espacios previamente inaccesibles para interacciones moleculares mejoradas y separación eficiente de mezclas de benceno y ciclohexano.

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Área de la Ciencia:

  • Ciencias de los materiales
  • Química supramolecular
  • Nanotecnología

Sus antecedentes:

  • Los marcos orgánicos covalentes (COF) están limitados por pequeñas distancias entre capas (3-6 Å) debido al apilamiento π-π, lo que restringe el acceso de los huéspedes.
  • Este confinamiento impide las interacciones con las caras extendidas de las capas de COF, lo que limita su aplicación en la separación y el confinamiento molecular.
  • Los COF actuales permiten principalmente la entrada / salida de los huéspedes a lo largo de la dirección z, dejando el plano x-y inaccesible.

Objetivo del estudio:

  • Desarrollar una estrategia para aumentar las distancias entre capas en los FOC.
  • Crear nanospacios accesibles dentro de los COF para mejorar las interacciones moleculares.
  • Mejorar la eficiencia de separación de los COF para moléculas invitadas específicas como el benceno y el ciclohexano.

Principales métodos:

  • Cobalto covalente 2D sintetizado en capas de porfirina mediante polimerización guiada por topología.
  • Se han ensamblado COF expandidos verticalmente utilizando pilares axiales bidentados unidos por enlaces de coordinación.
  • Utilizó sorción de vapor, experimentos innovadores y estudios computacionales para analizar las propiedades del marco y el rendimiento de la separación.

Principales resultados:

  • Se crearon con éxito COF expandidos verticalmente reemplazando pilas π-π con enlaces de coordinación.
  • Se obtienen aperturas discretas entre capas definidas por la longitud del pilar, abriendo capas intermedias previamente inaccesibles.
  • Se ha demostrado una separación eficiente de mezclas de benceno y ciclohexano en condiciones ambientales debido a las interacciones entre capas mejoradas.

Conclusiones:

  • Los COF expandidos verticalmente ofrecen una nueva plataforma para el confinamiento y la separación molecular mediante la creación de capas intermedias accesibles.
  • La estrategia de usar enlaces de coordinación para expandir los COF permite interacciones supramoleculares con los planos π expuestos.
  • Las ranuras optimizadas entre capas en estos marcos expandidos mejoran la selectividad para separar mezclas como el benceno y el ciclohexano.