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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Elucidación de un sistema de cobalto de espín bajo (II) en una geometría tetraédrica distorsionada
David M Jenkins1, Angel J Di Bilio, Matthew J Allen
1Division of Chemistry and Chemical Engineering, Arnold and Mabel Beckman Laboratories of Chemical Synthesis, California Institute of Technology, Pasadena, California 91125, USA.
Journal of the American Chemical Society
|December 19, 2002
Resumen
Este estudio introduce nuevos complejos de cobalto (II) con un ligando [PhBP (III) ] único, revelando estados básicos dobles sin precedentes en estructuras pseudotetraédricas y estados básicos triples en formas diméricas. Estos hallazgos avanzan en la comprensión de las propiedades electrónicas complejas del cobalto.
Área de la Ciencia:
- Coordinación Química de la Coordinación
- Química organometálica Química orgánica de los metales.
- Química Inorgánica La Química Inorgánica es la química inorgánica.
Sus antecedentes:
- Investigar las propiedades electrónicas y estructurales de los complejos divalentes de cobalto (II) es crucial para comprender su reactividad y sus aplicaciones potenciales.
- La influencia de los ligandos donantes de campo fuerte, aniónicos, tris (((fosfina)) en las configuraciones electrónicas del centro del metal sigue siendo un área de investigación activa.
- Los estudios previos sobre complejos de cobalto de 4 coordenadas ((II) con estados de base dobles se centraron principalmente en geometrías planas cuadradas.
Objetivo del estudio:
- Para sintetizar y caracterizar nuevos complejos divalentes de cobalto (II) con el ligando [PhBP (III) ].
- Para explorar los fenómenos estructurales y electrónicos que surgen del campo fuerte, el ligando donante aniónico tris (((fosfina).
- Para investigar las configuraciones de espín del estado fundamental y el comportamiento de la solución de estos complejos de cobalto.
Principales métodos:
- Síntesis de complejos de cobalto (II) con el ligando [PhBP (III) ].
- Caracterización estructural del estado sólido mediante difracción de rayos X.
- Análisis espectroscópico que incluye SQUID, EPR y espectroscopia óptica.
- Estudios de estado de solución para determinar los equilibrios monómero/dimérico y los estados de espín.
Principales resultados:
- El complejo pseudotetraédrico de cobalto (II) [PhBP (III) ] CoI exhibe un raro estado de base doble.
- Los complejos de bromuro dimérico y cloruro ([PhBP(3)]Co(mu-X))(2) muestran estados tripletos en estado sólido, pero existen como especies monoméricas de baja espina en solución.
- Los estudios de oxidación revelan la modificación del ligando y la formación de complejos de cobalto de alto espín (II).
- El ligando [PhBP(3)] induce un fuerte campo de ligando y distorsión axial, favoreciendo los estados básicos dobles en complejos monoméricos.
Conclusiones:
- El ligando [PhBP(3)] imparte un campo de ligando único y fuerte a los complejos divalentes de cobalto, distinto de otros ligandos de fosfina o borato.
- La combinación de un fuerte campo de ligando y la distorsión axial por el ligando [PhBP(3)] permite el acceso a estados inusuales de doble base en complejos pseudotetraédricos de cobalto (II).
- Estos hallazgos amplían la comprensión del control del estado de espín en la química de coordinación y ofrecen nuevas vías para el diseño de materiales a base de cobalto.
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