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La conversión de estado de espín inducida por la foto en complejos de metales de transición solvados probada a través
Nils Huse1, Tae Kyu Kim, Lindsey Jamula
1Ultrafast X-ray Science Lab, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. nhuse@lbl.gov
Journal of the American Chemical Society
|April 30, 2010
Resumen
El cruce de espín fotoinducido en un complejo de hierro se observó utilizando espectroscopia de rayos X. Este estudio revela cambios en la estructura electrónica y las longitudes de enlace durante la transición ultra rápida a un estado de alto espín.
Área de la Ciencia:
- La fotoquímica es la fotoquímica.
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- Los complejos de polipiridil de hierro (II) exhiben fenómenos de cruce de espín.
- Comprender la dinámica del cruce de espín es crucial para la electrónica molecular y la catálisis.
Objetivo del estudio:
- Para investigar el cruce de espín fotoinducido de la fase de solución en [Fe(tren(py) ((3)) ]^2+.
- Para dilucidar los cambios electrónicos y estructurales durante la transición de espín bajo a espín alto utilizando espectroscopia de resolución temporal.
Principales métodos:
- Espectroscopia de absorción de rayos X suave en picosegundos.
- Cálculos múltiple de transferencia de carga.
- Estudio de los complejos de modelos de espín bajo y alto.
Principales resultados:
- Se observó una conversión fotoinducida de un estado de espín bajo (1A1) a un estado de espín alto (5T2).
- Se midió una reducción de ~1 eV en la división del campo de ligando en el estado de alto espín.
- Se observó directamente una reducción de la superposición orbital Fe-3d/N-2p, consistente con el aumento de la longitud del enlace Fe-N.
Conclusiones:
- El cruce de espín implica una reducción en la donación sigma compensada por una atenuada unión pi-back.
- La espectroscopia de absorción de rayos X suave con resolución de tiempo es efectiva para estudiar reacciones fotoquímicas ultrarrápidas en fase líquida.
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