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El marco orgánico covalente de Viologen media la transferencia de electrones inducida por la luz del infrarrojo

Zhibei Zhou¹, Zitong Wang¹, Abigail L Blenko¹

¹Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States.

Journal of the American Chemical Society

|March 18, 2025

Resumen

Este estudio introduce un nuevo marco orgánico covalente de porfirina (Vio-COF) que absorbe la luz infrarroja cercana. Este material cataliza eficientemente las reacciones de acoplamiento oxidativo utilizando luz visible, ofreciendo una alternativa sostenible.

Área de la Ciencia:

Ciencias de los materiales
Fotocatálisis
Química orgánica

Sus antecedentes:

La luz del infrarrojo cercano (NIR) ofrece ventajas para las fotorreacciones, incluida una penetración más profunda y menos reacciones secundarias.
Los marcos orgánicos covalentes existentes (COF) absorben principalmente en el espectro UV-V, lo que limita su uso con la luz NIR.
El desarrollo de fotocatalizadores que absorban NIR es crucial para expandir las transformaciones químicas impulsadas por la luz.

Objetivo del estudio:

Diseñar y sintetizar un nuevo marco orgánico covalente (COF) capaz de absorber la luz del infrarrojo cercano (NIR).
Investigar la actividad fotocatalítica del COF absorbente de NIR en las reacciones de acoplamiento oxidativo.
Explorar el mecanismo detrás del rendimiento catalítico mejorado debido a la estructura del marco.

Principales métodos:

Síntesis de un COF de porfirina ligado al viólogo (Vio-COF) utilizando un proceso de transferencia de carga de enlace a enlace.
Caracterización de las propiedades ópticas de Vio-COF, confirmando la absorción NIR hasta 998 nm.
Evaluación del rendimiento de Vio-COF en reacciones de amidación oxidativa aeróbica y acoplamiento de aminas bajo irradiación NIR.

Principales resultados:

Vio-COF exhibe un nuevo efecto de hiperporfirina, extendiendo la absorción en la región NIR.
La separación de cargas inducida por la luz en el Vio-COF genera radicales de superóxido para la catálisis.
Vio-COF demuestra una eficiencia catalítica superior en las reacciones de acoplamiento oxidativo en comparación con los catalizadores homogéneos y es reciclable durante al menos seis ciclos.

Conclusiones:

Se ha desarrollado una nueva clase de COF absorbentes de NIR, superando las limitaciones de los materiales absorbentes de UV.
La estructura Vio-COF facilita la fotocatálisis eficiente bajo luz NIR, impulsada por un efecto de hiperporfirina y la proximidad de los sitios activos.
Este trabajo allana el camino para utilizar la luz NIR abundante en procesos catalíticos sostenibles, particularmente para reacciones de acoplamiento oxidativo.

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