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Modulación termodinámica de la activación de dihidrógeno a través del diseño racional de ligandos en complejos
Philip M Keil1, Sophia Ezendu2, Annika Schulz1
1Fakultät für Chemie, Technische Universität München, Lichtenbergstraße 4, 85748 Garching bei München, Germany.
Journal of the American Chemical Society
|August 6, 2024
Resumen
Los nuevos ligandos de germileno quelatantes permiten a los complejos de níquel activar el dihidrógeno de manera reversible. Las propiedades electrónicas de los ligandos ajustan esta activación, afectando la eficiencia de deshidroacoplamiento catalítico para el fenilsilano.
Área de la Ciencia:
- Química organometálica
- Diseño del ligando
- Catálisis
Sus antecedentes:
- Desarrollo de nuevos ligandos de germilenos quelatantes con función de arilo.
- Síntesis de los correspondientes complejos de 16 electrones (Ni) que incorporan estos ligandos.
Objetivo del estudio:
- Investigar la activación cooperativa y reversible del dihidrógeno en la interfaz germileno-níquel.
- Explorar la modulación de la termodinámica de activación de dihidrógeno mediante la sintonización de las propiedades electrónicas de los ligandos de germileno.
- Para demostrar la utilidad de esta modulación en las reacciones de deshidroacoplamiento catalítico.
Principales métodos:
- Síntesis de complejos de Ni(0) con ligandos de germilenos.
- Análisis espectroscópicos que incluyen RMN (Van't Hoff, 31P) y absorción UV/vis.
- Estudios computacionales (DFT) para determinar las órdenes y cargas de los bonos.
- Deshidroacoplamiento catalítico del fenilsilano.
Principales resultados:
- Desarrollo y síntesis exitosos de complejos de germileno-Ni.
- Demostración de la activación cooperativa y reversible del dihidrógeno en condiciones suaves.
- Correlación entre las propiedades electrónicas del ligando (carácter de retirada de electrones) y la exergonicidad de la activación de dihidrógeno.
- Identificación de una relación entre la termodinámica de activación de dihidrógeno y la eficiencia catalítica en el deshidroacoplamiento de fenilsilano.
Conclusiones:
- El diseño del ligando de germileno modula significativamente la activación del dihidrógeno en el centro de Ni.
- Los ligandos que retiran electrones aumentan la exergonicidad de la activación del dihidrógeno.
- La eficiencia del catalizador en el deshidroacoplamiento del fenilsilano está inversamente relacionada con la favorabilidad de la activación del dihidrógeno, destacando la eliminación de H2 como limitante de la velocidad.
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