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Cobalto (III) Complejo de carbenos con una estructura de estado excitado electrónico similar a los compuestos de
Narayan Sinha1, Björn Pfund1, Christina Wegeberg1
1Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland.
Journal of the American Chemical Society
|May 27, 2022
Resumen
Los investigadores desarrollaron un nuevo complejo de cobalto (III) con propiedades fotoactivas de transferencia de carga de metal a ligando (MLCT), similares a los complejos de iridio. Este avance ofrece nuevas posibilidades para los metales de transición de primera fila en fotoquímica.
Área de la Ciencia:
- Química inorgánica
- La fotoquímica
- Ciencias de los materiales
Sus antecedentes:
- Los complejos organometálicos de iridio ((III) son conocidos por estados excitados fotoactivos con carácter de transferencia de carga de metal a ligando y intraligando (MLCT / ILCT), lo que permite aplicaciones en fotofísica y fotoquímica.
- Los complejos de cobalto (III) con propiedades de estado excitado MLCT similares están en gran parte inexplorados, a pesar de la configuración electrónica d6 de bajo espín compartida con el iridio (III).
Objetivo del estudio:
- Sintetizar y caracterizar un complejo de cobalto exhibiendo estados excitados de MLCT fotoactivos.
- Investigar las propiedades fotofísicas y fotoquímicas del complejo de cobalto.
- Explorar nuevos principios de diseño de ligandos para complejos de metales de transición de primera fila con características fotofísicas similares a las de los metales del grupo platino.
Principales métodos:
- Síntesis de un complejo robusto de cobalto (III), [Co] (L) (CNC) (sub) 2 (sub) (PF) (sub) 6 (sub), utilizando un ligando quelato tridentado rígido (L) (CNC).
- Estudios estructurales, electroquímicos y de absorción transitoria frente a los rayos UV.
- Análisis comparativo con complejos de hierro (II) isoelectrónicos, específicamente [Fe (L) (CNC) (sub) 2 (sub) ] (PF (sub) 6 (sub))
Principales resultados:
- El complejo de cobalto sintetizado, [CoL] [CNC] [sub2] [PF] [sub6] exhibe un estado excitado fotoactivo con un carácter significativo de MLCT.
- El estado MLCT en el complejo de cobalto (III) es notablemente de larga duración en comparación con los complejos análogos de hierro (II), debido a la reducción de la desactivación en estados centrados en metales más bajos.
- El estado MLCT participa directamente en las reacciones de transferencia de electrones fotoinducidas.
Conclusiones:
- Los complejos de cobalto (III) pueden diseñarse para poseer estados de MLCT fotoactivos de larga duración, análogos a los complejos de iridio.
- El ligando desarrollado (LCNC) facilita la creación de complejos robustos de cobalto con propiedades fotofísicas deseables.
- Esta investigación proporciona información sobre el diseño de ligandos para metales de transición de primera fila, lo que permite aplicaciones fotofísicas y fotoquímicas previamente dominadas por metales del grupo platino.
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