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Estructura y dinámica del estado MLCT de un complejo de cobre (I) diimine caracterizado por espectroscopias de rayos
Lin X Chen1, George B Shaw, Irina Novozhilova
1Chemistry Division and Material Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, USA. lchen@anl.gov
Journal of the American Chemical Society
|June 5, 2003
Resumen
El estudio revela la estructura de un complejo de cobre fotoexcitado, mostrando un ion de cobre penta-coordinado en el estado de transferencia de carga de metal a ligando. Esto confirma una estructura "exciplex" y detalla su evolución dinámica y decaimiento.
Área de la Ciencia:
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- La fotoquímica es la fotoquímica.
- Química computacional es la química computacional.
Sus antecedentes:
- Los estados de transferencia de carga de metal a ligando (MLCT) son cruciales en la fotoquímica.
- Comprender la dinámica del estado excitado y las estructuras de los complejos de cobre es vital para sus aplicaciones.
- El complejo [Cu ((I) ((dmp) 2) ((+)) exhibe interesantes propiedades fotofísicas.
Objetivo del estudio:
- Para investigar la estructura molecular y la dinámica del estado MLCT fotoexcitado de [Cu(I) ((dmp) 2) ((+).
- Para dilucidar la evolución estructural desde el estado de fotoexcitación al estado MLCT térmicamente equilibrado.
- Para confirmar la estructura propuesta de "exciplex" en el acetonitrilo.
Principales métodos:
- Espectroscopia de absorción de rayos X de bomba de sonda de dominio de tiempo con una resolución de tiempo de 100 ps.
- Espectroscopia óptica transitorio de cinco segundos.
- Cálculos de la teoría funcional de la densidad (DFT).
Principales resultados:
- El estado MLCT térmicamente equilibrado presenta un ion de cobre penta-coordinado con una distancia de enlace Cu-N más corta (0.04 Å) en comparación con el estado fundamental.
- La espectroscopia de femtosegundos reveló constantes de tiempo de 500-700 fs, 10-20 ps y 1.6-1.7 ns para la evolución del estado MLCT.
- Los cálculos de DFT apoyaron la estructura exciplex y la transferencia de carga cuantificada tras la fotoexcitación.
Conclusiones:
- El estudio confirma la estructura "exciplex" del estado MLCT en el acetonitrilo.
- Los hallazgos proporcionan información sobre la relajación estructural y las vías de decaimiento del estado excitado.
- La dinámica de transferencia de carga es consistente con los cambios observados entre los estados de oxidación de cobre (I) y cobre (II).
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