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Control de iones metálicos de la polarización de espín de electrones fotoinducida en estados de tierra electrónicos
Martin L Kirk1,2, David A Shultz3, Ju Chen1
1Department of Chemistry and Chemical Biology, The University of New Mexico, Albuquerque, New Mexico 87131-0001, United States.
Journal of the American Chemical Society
|July 12, 2021
Resumen
El ion metálico en los complejos de radicales cromóforos controla la polarización del espín de los electrones (ESP). Los complejos de paladio muestran un ESP emisor débil, mientras que los complejos de platino muestran un ESP absorbente fuerte debido a las interacciones de espín-órbita.
Área de la Ciencia:
- La fotoquímica
- Química del espín
- Ciencias de los materiales
Sus antecedentes:
- Los complejos de radicales cromóforos exhiben polarización de espín de electrones fotoinducida (ESP).
- El doble de estado básico electrónico (2S0/D0) de estos complejos está influenciado por iones metálicos.
- Los radicales orgánicos como el nitróxido de nitronio (NN) son componentes clave.
Objetivo del estudio:
- Investigar cómo el cambio del ion metálico (Pd vs. Pt) afecta el signo y la intensidad de la ESP fotoinducida.
- Comprender los mecanismos detrás de la percepción extrasensorial emisora frente a la absorbente en estos complejos.
- Para correlacionar los fenómenos de polarización de espín con las transiciones electrónicas y el acoplamiento de espín-órbita.
Principales métodos:
- Síntesis de complejos (bpy) M ((CAT-m-Ph-NN) con M = PdII y PtII.
- Fotoexcitación de complejos utilizando luz visible.
- Análisis espectroscópico para detectar y cuantificar la polarización del espín de los electrones (ESP).
Principales resultados:
- Ambos complejos Pd y Pt forman un estado excitado de doble separado de carga (S1) tras la fotoexcitación.
- Se observó una ESP emisora débil para el complejo de paladio (1-Pd).
- Se generó una fuerte ESP absorbente en el complejo de platino (1-Pt).
Conclusiones:
- La identidad de iones metálicos controla significativamente el tipo y la magnitud de la ESP.
- La división del campo cero influye en las transiciones en el complejo de paladio.
- Las interacciones de espín-órbita en el complejo de platino son cruciales para generar una fuerte ESP absorbente.
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