Ajuste del estado de espín en iones pseudotetraédricos d(7): examinando los fenómenos estructurales y magnéticos de los sistemas de cuatro coordenadas [BP3]CoII-X
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Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
David M Jenkins1, Jonas C Peters
1Division of Chemistry and Chemical Engineering, Arnold and Mabel Beckman Laboratories of Chemical Synthesis, California Institute of Technology, Pasadena, CA 91125. USA.
Journal of the American Chemical Society
|May 12, 2005
Resumen
Este estudio explora los complejos pseudotetraédricos de cobalto (II) con ligandos de tris (II) fosfino-borato. Los investigadores encontraron que ambos estados de espín S = 1/2 y S = 3/2 son accesibles, con algunos complejos que exhiben un comportamiento de cruce de espín.
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:
- Los complejos pseudo-tetraédricos de cobalto (II) son de interés debido a sus diversas propiedades electrónicas y estructurales.
- El sistema de ligando de tris ((phosphino) borato ([BP ((3))) ofrece entornos estéricos y electrónicos únicos para los centros metálicos.
Objetivo del estudio:
- Síntesis y caracterización de una serie de complejos pseudotetraédricos de cobalto (II) soportados por los ligandos [PhBP (III) ] y [PhBP (iPr) (III) ].
- Para investigar la estructura electrónica, el estado de espín y las distorsiones geométricas de estos complejos de cobalto.
- Para explorar la relación entre la estructura del ligando, la geometría de coordinación y las propiedades magnéticas.
Principales métodos:
- Síntesis de nuevos complejos de cobalto ((II) aryloxide, siloxide, ariltiolato y sililtiolato.
- Caracterización utilizando las mediciones estándar (1)H RMN, ópticas, electroquímicas y magnéticas de la solución.
- Estudios de magnetización por resonancia paramagnética de electrones de baja temperatura (EPR) y por dispositivo de interferencia cuántica superconductor de temperatura variable (SQUID).
- Análisis de difracción de rayos X monocristalino a baja temperatura.
- Teoría Funcional de Densidad (DFT) cálculos de la estructura electrónica.
Principales resultados:
- Se sintetizó y caracterizó una serie de complejos pseudotetraédricos de cobalto ((II) con ligandos [PhBP ((3)) ] y [PhBP ((iPr) ((3)).
- Los complejos exhiben dos tipos principales de distorsión: paraguas y fuera del eje.
- Los complejos distorsionados de paraguas pueden acceder tanto a los estados básicos S = 1/2 como S = 3/2, influenciados por la naturaleza y la denticidad del ligando.
- Los complejos distorsionados fuera del eje pueblan exclusivamente un estado básico de S = 1/2.
- Los siloxidos pseudotetraédricos muestran un cruce de espín gradual en el estado sólido.
- Los cálculos de DFT apoyan las relaciones de estructura electrónica con otras geometrías de coordinación de cobalto.
Conclusiones:
- La geometría de coordinación y el entorno de los ligandos influyen significativamente en el estado de espín de los complejos pseudotetraédricos de cobalto.
- El comportamiento de cruce de espín se observó en complejos específicos de siloxido pseudotetraédrico.
- El marco de ligandos [BP(3) ] proporciona una plataforma versátil para ajustar las propiedades de los complejos de cobalto.
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