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Aniones de polisulfuro como catalizadores fotorredóxicos de luz visible para acoplamientos cruzados de arilo

Haoyu Li¹, Xinxin Tang², Jia Hao Pang¹

¹Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore.

Journal of the American Chemical Society

|December 28, 2020

Resumen

Los aniones de polisulfuro, como los dianiones de tetrasulfuro (S₄^2-), son ahora catalizadores de fotorreducción de luz visible. Permiten reacciones de acoplamiento cruzado de arilo, borilación e hidrogenación a través de la reducción de un solo electrón de haluros de arilo.

Área de la Ciencia:

Catalización por fotorreducción
Síntesis orgánica
La electroquímica

Sus antecedentes:

Los aniones polisulfuro poseen propiedades redox únicas, exploradas principalmente para las baterías de metal alcalino-azufre.
Su aplicación en la catálisis redox para la síntesis de moléculas pequeñas está limitada por potenciales electroquímicos de estado fundamental subóptimos.
Ciertos polisulfuros muestran fotoabsorción en el espectro de luz visible.

Objetivo del estudio:

Investigar el potencial de los aniones polisulfuro como catalizadores fotorreductivos de la luz visible.
Desarrollar nuevos sistemas catalíticos para reacciones de acoplamiento cruzado de arilo utilizando polisulfuros.
Para explorar los mecanismos catalíticos redox que involucran los radicales polisulfuro intermedios.

Principales métodos:

Irradiación de luz visible de dianiones tetrasulfuro (S₄^2-) para lograr la fotoexcitación.
Reducción de un solo electrón de haluros de arilo facilitada por los polisulfuros fotoexcitados.
Catálisis redox que involucra las parejas redox S2- y S3-.

Principales resultados:

Demostración de los aniones polisulfuro como catalizadores fotorreductivos eficaces para la luz visible.
Ejecución exitosa de reacciones de acoplamiento cruzado de arilo, incluida la formación de (hetero) biarilo.
Expansión de las aplicaciones catalíticas para incluir la berilación y la hidrogenación de haluros de arilo.
Elucidación del ciclo catalítico en el que intervienen los principales radicales polisulfuro.

Conclusiones:

Los aniones polisulfuro pueden utilizarse como eficientes catalizadores fotorreductivos de luz visible.
Este enfoque proporciona una nueva vía para activar haluros de arilo en la síntesis orgánica.
La metodología desarrollada ofrece nuevas oportunidades para transformaciones químicas sostenibles y eficientes.

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