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Escisión electroquímica y electrostática de las alkoxiaminas
Long Zhang1,2, Eduardo Laborda3, Nadim Darwish1
1Department of Chemistry, Curtin University , Bentley, Western Australia 6102, Australia.
Journal of the American Chemical Society
|December 21, 2017
Resumen
Las alkoxiaminas liberan nitróxidos rápidamente después de la oxidación de un electrón. Las fuerzas electrostáticas en las interfaces electrificadas influyen significativamente en esta escisión del enlace C-ON, lo que permite el desenmascaramiento controlado por redox.
Área de la Ciencia:
- La electroquímica
- Ciencias de los materiales
- Química Física
Sus antecedentes:
- Las alkoxiaminas son fuentes in situ cruciales de nitróxidos para la ciencia de los polímeros y los materiales.
- Comprender sus vías de descomposición es clave para controlar la generación de óxido nitroso.
Objetivo del estudio:
- Investigar el mecanismo de descomposición de la alkoxiamina después de la oxidación de un electrón.
- Para aclarar el papel de las interacciones electrostáticas en la escisión del enlace C-ON.
- Para explorar el potencial de la división de la alkoxiamina controlada por redox.
Principales métodos:
- Técnicas electroquímicas que incluyen la voltametría y el análisis transitorio de corriente-tiempo.
- Simulaciones digitales de los datos experimentales.
- Cálculos químicos cuánticos de alto nivel.
- Experimentos de ruptura de unión de una sola molécula (STM-BJ) en disolventes de bajo dieléctrico.
Principales resultados:
- La oxidación de un electrón de las alkoxiaminas genera radicales cationales que se fragmentan rápidamente en nitróxidos y carbocationes.
- La descomposición unimolecular que produce TEMPO es extremadamente rápida e irreversible.
- El modelado computacional requiere tener en cuenta el entorno electrostático para que coincida con la cinética experimental.
- Los experimentos STM-BJ confirman la influencia significativa de las fuerzas electrostáticas en la lisis de enlaces C-ON.
Conclusiones:
- Las interacciones electrostáticas juegan un papel crítico en el paso químico siguiente a la oxidación de la alkoxiamina.
- La magnitud de este efecto catalítico se puede cuantificar utilizando técnicas eléctricas.
- Este trabajo sugiere un mecanismo de conmutación redox para la escisión controlada de la alkoxiamina en las interfaces electrificadas.
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