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Sustitución de hierro por sodio en un complejo heterodinuclear de sodio y hierro con puente de carboxilato
Jeremy J Kodanko1, Dong Xu, Datong Song
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Journal of the American Chemical Society
|November 17, 2005
Resumen
Este estudio detalla un nuevo complejo de hierro-sodio conectado por carboxilatos de triptceno. El sodio puede ser sustituido por el hierro (II) a través de un mecanismo disociativo, formando un complejo di-hierro (II).
Área de la Ciencia:
- Coordinación Química de la Coordinación
- Química organometálica Química orgánica de los metales.
- Química supramolecular de las moléculas.
Sus antecedentes:
- Desarrollo de nuevos complejos metálicos con propiedades estructurales y electrónicas únicas.
- Exploración de sistemas heterodinucleares con puentes de carboxilato para aplicaciones catalíticas o de materiales.
Objetivo del estudio:
- Para sintetizar y caracterizar estructuralmente un nuevo complejo heterodinuclear de hierro-sodio con puente de carboxilato.
- Para investigar la reacción de sustitución del sodio por el hierro (II) en el complejo sintetizado.
- Para dilucidar el mecanismo y la cinética de la reacción de sustitución.
Principales métodos:
- Síntesis y difracción de rayos X monocristalino para la caracterización estructural.
- UV-vis, IR y espectrometría de masas (MS) para el monitoreo de la reacción.
- Espectroscopia de flujo detenido para determinar la cinética de la reacción y los parámetros de activación.
Principales resultados:
- Síntesis y caracterización exitosas del complejo heterodinuclear [NaFe (((PIC2DET)) ((mu-O2CTrp)) 3) (2).
- Identificación de un isómero de enlace a través de la cristalografía de rayos X.
- Observación de la sustitución de sodio por hierro (II) que da como resultado [Fe2 (PIC2DET) ] (mu-O2CTrp) [3] [OTf] (3).
- Los estudios cinéticos revelaron un mecanismo disociativo (kobs = 21 +/- 2 s-1) con entalpía positiva y entropía negativa de activación.
Conclusiones:
- El estudio presenta un nuevo complejo heterodinuclear hierro-sodio con una estructura definida.
- La reacción de sustitución procede a través de una vía disociativa, lo que indica labilidad del ion sodio.
- Los hallazgos proporcionan información sobre la reactividad y las vías mecánicas de los complejos metálicos puentes de carboxilato.
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