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Intercambio de estado excitado en el renio (I) Complejos de bipiridil con sustitutos donante-donante y
Joshua J Sutton1,2, Dan Preston1,2, Philipp Traber3
1Department of Chemistry, University of Otago, Dunedin 9016, New Zealand.
Journal of the American Chemical Society
|June 11, 2021
Resumen
El estudio presenta las propiedades ópticas de los complejos de renio con los ligandos de trifenilamina (TPA) y benzotiadiazol (BTD). Se observaron estados excitados dependientes del disolvente, ya sea transferencia de carga de metal a ligando (MLCT) o transferencia de carga intraligando (ILCT).
Área de la Ciencia:
- La fotoquímica
- Química de coordinación
- Espectroscopia
Sus antecedentes:
- Los complejos de polipiridil de renio están ampliamente estudiados por sus propiedades fotofísicas.
- Los sustituyentes de ligando de afinación influyen en las características de transferencia de carga y el comportamiento de estado excitado.
- La comprensión de los efectos del disolvente es crucial para el control de los procesos fotofísicos.
Objetivo del estudio:
- Investigar las propiedades ópticas y de estado excitado de dos complejos de renio: ReTPA2 y ReTPA-BTD.
- Para aclarar la naturaleza de los estados excitados (MLCT vs. ILCT) y su dependencia del disolvente.
- Explorar el papel del acoplamiento de espín-órbita en la conmutación de transferencia de carga controlada por solvente.
Principales métodos:
- Espectroscopia de absorción y emisión UV-Vis
- Espectroscopia Raman de resonancia
- Espectroscopia infrarroja con resolución de tiempo
- Teoría de la función de densidad (DFT) y cálculos de DFT dependientes del tiempo (TDDFT)
Principales resultados:
- ReTPA2 exhibe intensas bandas de transferencia de carga intraligando (ILCT) a 460 nm con un pequeño solvatocromismo.
- ReTPA-BTD muestra transiciones ILCT más débiles, asignadas como TPA → bpy.
- Se observaron dos estados emisores para ambos complejos, con la intensidad modulada por el disolvente.
- La espectroscopia IR con resolución de tiempo reveló estados MLCT en CH2Cl2 y estados ILCT en MeCN.
- Los cálculos de DFT confirmaron el cambio inducido por el disolvente de los estados de transferencia de carga a través del acoplamiento de órbita de giro.
Conclusiones:
- Las propiedades ópticas y la dinámica del estado excitado de ReTPA2 y ReTPA-BTD están significativamente influenciadas por la sustitución del ligando y la polaridad del disolvente.
- La polaridad del disolvente dicta la naturaleza de los estados excitados (MLCT vs. ILCT) a través de la modulación del acoplamiento de espín-órbita.
- Este estudio demuestra una estrategia para controlar los estados de transferencia de carga en los complejos de renio mediante una selección juiciosa del disolvente.
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