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Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
El ajuste del disolvente de la región de Marcus normal a la invertida de la transferencia intramolecular de
Imma Ratera1, Christian Sporer, Daniel Ruiz-Molina
1Institut de Ciència de Materials de Barcelona, Campus Universitari de Ballaterra, 08193 Bellaterra, Catalonia, Spain.
Journal of the American Chemical Society
|April 25, 2007
Resumen
Este estudio detalla dos díadas paramagnéticas donante-receptor, revelando la transferencia de electrones inducida por la luz. La polaridad del disolvente influye en su dinámica energética, cambiando entre las regiones Marcus normales e invertidas.
Área de la Ciencia:
- La fotoquímica y la fotofísica.
- Química organometálica Química orgánica de los metales.
- Espectro electroquímica electroquímica.
Sus antecedentes:
- Las díadas donante-receptor son cruciales para el estudio de los procesos de transferencia de electrones.
- El ferroceno y los radicales trifenilmetilo policlorados ofrecen propiedades redox y electrónicas sintonizables.
- Comprender los efectos del disolvente en estas propiedades es clave para la electrónica molecular.
Objetivo del estudio:
- Para sintetizar y caracterizar dos diadas paramagnéticas neutras de donante y receptor.
- Para investigar la dependencia del disolvente de sus propiedades espectroscópicas y redox.
- Para dilucidar los mecanismos de transferencia de electrones fotoinducidos y la dinámica de la energía.
Principales métodos:
- Síntesis de diadas donante-aceptor basadas en ferroceno y no metilferroceno.
- Espectroscopia de infrarrojo cercano (NIR) para sondear las transiciones electrónicas.
- Voltametría cíclica para determinar los potenciales redox.
- Espectroscopia de absorción transitoria de picosegundos para estudiar la cinética de recombinación de carga.
Principales resultados:
- Las amplias absorciones de NIR indican la transferencia intramolecular de electrones del donante al aceptador.
- Se observaron dos procesos de redox reversibles de un electrón para cada díada.
- Se cuantificó la dependencia de la polaridad del disolvente de los potenciales redox y las energías de reorganización.
- Se observó un cambio de la región normal a la región invertida de Marcus con el cambio de la polaridad del disolvente.
- El estado de carga separada fue observado directamente, confirmando la transferencia de electrones fotoinducida.
Conclusiones:
- Las díadas estudiadas exhiben una eficiente transferencia de electrones fotoinducida.
- La polaridad del disolvente tiene un impacto significativo en el equilibrio energético y la dinámica de transferencia de electrones.
- El cambio observado en las regiones de Marcus proporciona información sobre los mecanismos de transferencia de carga.
- La observación directa del estado de carga separada valida el modelo de transferencia de electrones fotoinducido.
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