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Introduction to Solid Supported Membrane Based Electrophysiology
Published on: May 11, 2013
Cruce entre sistemas frente a la transferencia de electrones en sistemas de donante-puente-aceptor basados en
Karin Pettersson1, Kristine Kilså, Jerker Mårtensson
1Department of Chemistry and Bioscience, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Journal of the American Chemical Society
|May 27, 2004
Resumen
La alteración del estado de espín de un aceptador de porfirina de hierro (III) en los sistemas de donante-puente-aceptador cambia significativamente los procesos fotofísicos. Los estados de espín bajo permiten la transferencia de electrones de largo alcance, mientras que los estados de espín alto mejoran el cruce intersistémico en el donante.
Área de la Ciencia:
- La fotoquímica es la fotoquímica.
- Química supramolecular de las moléculas.
- Los sistemas de cruce de espín se cruzan.
Sus antecedentes:
- Los sistemas de donante-puente-aceptor (D-B-A) son cruciales para comprender los procesos de transferencia de carga.
- El estado de espín de los centros metálicos puede influir dramáticamente en el comportamiento molecular y la reactividad.
- Las porfirinas de hierro (III) ofrecen estados de espín sintonizables a través de la coordinación de ligandos.
Objetivo del estudio:
- Para investigar el impacto del estado de espín del aceptador en las vías fotofísicas en los sistemas D-B-A.
- Aclarar el papel de los aceptores de porfirina de alto espín frente a los de hierro de bajo espín en la transferencia de carga y el cruce entre sistemas.
- Explorar la influencia de los ligandos puentes en estos procesos dependientes del espín.
Principales métodos:
- Síntesis y caracterización de sistemas D-B-A con donantes de porfirina de zinc y aceptores de porfirina de hierro.
- Ajuste del estado de espín del aceptador de porfirina de hierro (III) mediante la coordinación de los ligandos de imidazol.
- Técnicas espectroscópicas con resolución de tiempo para monitorear procesos fotofísicos como la transferencia de electrones y el cruce entre sistemas.
Principales resultados:
- Los aceptores de porfirina de hierro de alto espín (III) mejoran significativamente el cruce intersistémico en el donante de porfirina de zinc.
- No se observó ninguna transferencia de electrones fotoinducida significativa al aceptor de porfirina de hierro de alto espín (III).
- Cambiar el aceptor a un estado de espín bajo facilita la transferencia de electrones de largo alcance en la escala de tiempo de picosegundos.
- Las tasas de cruce intersistémico vuelven a la normalidad en el sistema de aceptación de bajo giro.
Conclusiones:
- El estado de espín del aceptor es un determinante crítico de las vías fotofísicas en los sistemas D-B-A.
- Las porfirinas de hierro de baja espina (III) promueven una eficiente transferencia de electrones de largo alcance.
- Las porfirinas de hierro de alto espín (III) influyen principalmente en el cruce intersistémico en la fracción donante.
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