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La estructura electrónica del complejo de hierro de cuatro coordenadas (I) soportado por un ligando de bis
Yumiko Nakajima1, Yoshihide Nakao, Shigeyoshi Sakaki
1Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Journal of the American Chemical Society
|July 3, 2010
Resumen
Se sintetizó y caracterizó un nuevo complejo de hierro (I) de 15 electrones, [FeBr (BPEP) ]. Su singular estructura trigonal monopiramidal surge de las interacciones del ligando pi del hierro, revelando un centro Fe (I) de alto espín.
Área de la Ciencia:
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- Química organometálica Química orgánica de los metales.
- Coordinación Química de la Coordinación
Sus antecedentes:
- Los complejos de hierro son cruciales en la catálisis y la ciencia de los materiales.
- Comprender las geometrías de coordinación inusuales y las estructuras electrónicas es clave para diseñar nuevas moléculas funcionales.
- La síntesis y caracterización de complejos de hierro de baja valencia ofrecen información sobre una nueva reactividad y unión.
Objetivo del estudio:
- Para sintetizar y caracterizar un complejo de hierro de 15 electrones con un centro formal Fe (I).
- Para aclarar las propiedades estructurales y electrónicas del complejo resultante, [FeBr(BPEP) ].
- Para investigar el papel de las interacciones metal-ligando en la determinación de la geometría del complejo.
Principales métodos:
- Reducción de un electrón de un precursor de dibromuro para obtener el complejo de hierro objetivo.
- Difracción de rayos X monocristalino para la determinación estructural.
- Magnetometría SQUID y espectroscopia Mossbauer para la caracterización electrónica.
- Cálculos de la Teoría Funcional de Densidad (DFT) para el análisis de la estructura electrónica.
Principales resultados:
- Síntesis exitosa del complejo de hierro (I) de 15 electrones [FeBr (BPEP) ].
- La difracción de rayos X reveló una geometría monopiramidal trigonal distorsionada alrededor del centro de hierro.
- La magnetometría confirmó un estado básico de alto espín S = 3/2, consistente con Fe (I).
- La espectroscopia de Mossbauer y los cálculos de DFT apoyaron la configuración electrónica Fe (I) de alto espín y resaltaron las orbitales moleculares deslocalizadas.
Conclusiones:
- El complejo de hierro sintetizado exhibe una inusual geometría de coordinación trigonal monopiramidal.
- La estructura distorsionada se atribuye a las interacciones efectivas pi-pi entre los orbitales de hierro d(z(2)) y los orbitales pi* del ligando BPEP.
- Este estudio proporciona información valiosa sobre el enlace y la estructura electrónica de los complejos de hierro de baja valencia.
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