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El mecanismo de activación de enlaces E-H (E = N, O) por un complejo de germanio corrole: un estudio experimental y

Huayi Fang¹, Huize Jing¹, Haonan Ge¹

¹†Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.

Journal of the American Chemical Society

|May 19, 2015

Resumen

Este estudio muestra que un nuevo complejo germanio-corol, (TPFC) Ge ((TEMPO), rompe eficientemente los enlaces N-H y O-H bajo luz visible. Esta reactividad es impulsada por un mecanismo de par radical que involucra la transferencia de electrones acoplados a protones.

Área de la Ciencia:

Química organometálica Química orgánica de los metales.
La fotoquímica es la fotoquímica.
Química Radical La Química Radical es una ciencia

Sus antecedentes:

Las reacciones mediadas por la luz visible son cruciales para la síntesis sostenible.
La activación del enlace E-H es una transformación fundamental en la química.
Los complejos germanio-corrol ofrecen propiedades fotofísicas únicas.

Objetivo del estudio:

Para investigar la reactividad de escisión de enlaces E-H inducida por la luz visible de (TPFC) Ge (TEMPO).
Para dilucidar el mecanismo de activación del enlace E-H por este complejo.
Explorar el alcance de los substratos de aminas y alcoholes activados por el sistema.

Principales métodos:

Síntesis y caracterización del complejo (TPFC) Ge ((TEMPO).
Experimentos fotoquímicos bajo irradiación de luz visible.
Espectroscopia de resonancia paramagnética de electrones (EPR) para la detección de radicales.
Cálculos de la Teoría Funcional de Densidad (DFT) para conocimientos mecanicistas.

Principales resultados:

El complejo (TPFC) Ge ((TEMPO) rompe eficientemente los enlaces N-H y O-H en varias aminas y alcoholes bajo luz visible.
Los estudios de EPR y DFT revelan la generación de un par de radicales [(TPFC) Ge] (((0))) / TEMPO (((•) a través de la fotoescisión del enlace Ge-O.
El mecanismo implica la coordinación del sustrato con el centro de germanio seguido de la escisión del enlace E-H a través de la transferencia de electrones acoplados a protones (PCET) mediada por el radical TEMPO.

Conclusiones:

La irradiación de luz visible de (TPFC) Ge (TEMPO) permite una activación eficiente de enlaces E-H en aminas y alcoholes.
La reacción procede a través de un novedoso mecanismo de pares de radicales iniciado por la fotoescisión del enlace Ge-O.
Este trabajo amplía la utilidad de los complejos germanio-corrol en la catálisis fotorredóxica y destaca el papel del PCET en la escisión de enlaces E-H.

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