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Observación de los estados excitados 1MLCT y 3MLCT en complejos de Mo2 y W2 cuádruplamente unidos
Matthew J Byrnes1, Malcolm H Chisholm, Judith A Gallucci
1Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210-1185, USA.
Journal of the American Chemical Society
|December 8, 2005
Resumen
Este estudio revela estados excitados de transferencia de carga de metal a ligando (MLCT) en complejos metálicos cuadruplemente unidos, actuando como moléculas orgánicas mediadas por metales con propiedades sintonizables.
Área de la Ciencia:
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- La fotoquímica es la fotoquímica.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- Los complejos metálicos cuadruplicados ofrecen estructuras electrónicas únicas.
- Las transiciones de transferencia de carga de metal a ligando (MLCT) son cruciales para las propiedades fotofísicas.
- Comprender los estados excitados en estos complejos es clave para diseñar nuevos materiales.
Objetivo del estudio:
- Investigar las propiedades fotofísicas de los complejos M(2)(O(2)C-Ar)(4) cuadruplamente unidos.
- Caracterizar la naturaleza y las vidas de los estados excitados en estos sistemas.
- Explorar el potencial de estos complejos como moléculas orgánicas mediadas por metales.
Principales métodos:
- Espectroscopia de absorción y emisión UV-Vis.
- Espectroscopia de absorción transitoria para detectar estados excitados de larga duración.
- Mediciones electroquímicas y cálculos de la teoría funcional de la densidad (DFT).
Principales resultados:
- La absorción de energía más baja se asigna a una transición (1) MLCT.
- Los complejos Mo(2) muestran estados excitados de corta duración (1) MLCT y de larga duración (3) MLCT.
- Los complejos W(2) exhiben un mayor acoplamiento espín-órbita y son más fáciles de oxidar.
- Se predice que el estado emisor (1) MLCT será un poderoso agente reductor.
Conclusiones:
- Esta es la primera observación de estados excitados del MLCT en complejos de enlaces cuádruples.
- Las propiedades fotofísicas se asemejan a las moléculas aromáticas orgánicas, lo que sugiere un carácter orgánico mediado por metales.
- La sintonización de las energías de estado excitado y los potenciales redox es alcanzable a través de la conjugación con el M(2) delta orbital.
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