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Tres estados de redox reversibles de complejos de dirodio con puente de tiolato sin enlaces metal-metal
1Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States.
Journal of the American Chemical Society
|August 14, 2020
Resumen
Este estudio informa de un complejo de rodio dinuclear único con un ligando puente que exhibe un comportamiento redox reversible, lo que permite el aislamiento de tres estados de oxidación distintos. Estos complejos muestran interesantes propiedades electrónicas y magnéticas, incluida la deslocalización de electrones y el acoplamiento antiferromagnético.
Área de la Ciencia:
- Química inorgánica
- Química de coordinación
- Ciencias de los materiales
Sus antecedentes:
- Los complejos dinucleares de rodio son de interés por sus propiedades catalíticas y electrónicas.
- Los ligandos puentes juegan un papel crucial en la determinación de la estructura y la reactividad de los complejos metálicos.
- Comprender el comportamiento redox en complejos metálicos es clave para diseñar nuevos materiales funcionales.
Objetivo del estudio:
- Sintetizar y caracterizar un nuevo complejo de rodio dinuclear con un ligando puente de 2-mercapto-6-metilpiridinato (mmp).
- Investigar las propiedades redox y las variaciones estructurales y electrónicas resultantes del complejo.
- Elucidar la estructura electrónica y el acoplamiento magnético en diferentes estados de oxidación.
Principales métodos:
- Síntesis del complejo dinuclear de rodio.
- Estudios electroquímicos para determinar el potencial redox.
- Difracción de rayos X de cristal único para elucidación estructural.
- Espectroscopia de resonancia paramagnética de electrones (EPR).
- Espectroscopia UV-Vis-NIR.
- Mediciones de la susceptibilidad magnética.
- Cálculos de la teoría funcional de la densidad (DFT).
Principales resultados:
- Aislamiento de tres complejos distintos (1, 2 y 3) correspondientes a los estados de oxidación Rh2 ((I, I), Rh2 ((I, II) y Rh2 ((II, II).
- El complejo 2 exhibe un carácter de valencia mixta sin precedentes con electrones no apareados deslocalizados.
- El complejo 3 muestra un fuerte acoplamiento antiferromagnético debido a una superposición orbital significativa, que carece de un enlace sigma Rh-Rh típico.
- Los datos espectroscópicos y magnéticos están respaldados por cálculos DFT.
Conclusiones:
- El complejo de rodio dinuclear con el ligando mmp demuestra una rica química redox y diversidad estructural.
- La capacidad de aislar estados redox distintos proporciona una plataforma para estudiar la deslocalización de electrones y las interacciones magnéticas.
- Este trabajo contribuye a la comprensión de la comunicación electrónica y la unión en sistemas de dirhodium.
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