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Cinco estados de oxidación de nitrógeno de nitro a amina: estabilización y reactividad de un complejo de

Joseph Zsombor-Pindera^1,2, Farshid Effaty¹, Léon Escomel¹

¹Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada.

Journal of the American Chemical Society

|October 30, 2020

Resumen

Este estudio introduce nuevos complejos de cobre con ligandos redox activos. Estos complejos permiten transformaciones químicas únicas de dos electrones a través de un mecanismo de lanzadera de cobre, demostrado en la catálisis de oxidación de alcohol.

Área de la Ciencia:

Química de coordinación
Química organometálica
Catálisis

Sus antecedentes:

Los ligandos no inocentes redox son cruciales para modular la reactividad del centro metálico en las metalloenzimas y la catálisis.
El desarrollo de nuevos marcos de ligandos que ofrezcan propiedades redox sintonizables es esencial para el avance de las aplicaciones catalíticas.

Objetivo del estudio:

Sintetizar y caracterizar nuevos complejos de cobre con un grupo de nitrógeno suspenso redox-activo.
Investigar la reactividad única de un intermediario metastable de cobre-arilo-hidroxilamina.
Para demostrar el potencial catalítico de estos complejos en las transformaciones químicas de dos electrones.

Principales métodos:

Síntesis de una serie de complejos de cobre con un marco de ligando común y diferentes estados redox de nitrógeno.
Caracterización de los complejos de cobre, incluidas las especies de cobre ((I) -arilhidroxilamina sin precedentes.
Estudios electroquímicos para sondear el comportamiento redox del ligando y el centro del metal.
Pruebas catalíticas para la oxidación del alcohol aeróbico.

Principales resultados:

Síntesis exitosa de complejos de cobre con un grupo de nitrógeno colgante capaz de acceder a cinco estados redox distintos.
Aislamiento y caracterización de un complejo de cobre ((I) -arilohidroxilamina estable, estabilizado por un enlace de hidrógeno intramolecular.
Demostración de una oxidación de dos electrones a un complejo de cobre (II) - (radical de arilnitrosilo), que puede disociarse.
Oxidación de alcohol aeróbico catalítico obtenido mediante un mecanismo de lanzadera de cobre (I/II) facilitado por la no inocencia y la hemilabilidad redox del ligando.

Conclusiones:

La combinación de no inocencia redox del ligando y hemilabilidad en complejos de cobre ofrece una poderosa estrategia para la catálisis.
El sistema desarrollado proporciona una plataforma para una química eficiente de dos electrones mediada por una lanzadera de cobre de un electrón.
Este trabajo abre nuevas vías para diseñar catalizadores para transformaciones redox desafiantes.

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