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Isómeros del estado de espín de CO2 químicamente separables
Amelia M Wheaton1, Jill A Chipman1, Rebecca K Walde1
1Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, United States.
Journal of the American Chemical Society
|September 19, 2024
Resumen
Los investigadores informan de los primeros isómeros de cobalto en estado de espín físicamente separables. Estos isómeros distintos, que surgen de un complejo Mo-Co, se pueden aislar debido a las diferencias en la solubilidad y las tasas de interconversión.
Área de la Ciencia:
- Química de coordinación
- Ciencias de los materiales
- Espectroscopia
Sus antecedentes:
- Los complejos de cruce de espín (SCO) exhiben estados de espín conmutables y cambios geométricos.
- Los isómeros de SCO generalmente se interconvierten rápidamente y son difíciles de separar debido a la polaridad similar.
Objetivo del estudio:
- Informar el primer ejemplo de isómeros de cobalto en estado de espín físicamente separables.
- Caracterizar estos isómeros y comprender los factores que permiten su separación.
Principales métodos:
- Síntesis de compuestos heterometálicos de Mo-Co.
- Magnetometría SQUID y espectroscopia EPR para la determinación del estado de espín.
- Cristalografía de rayos X para analizar las diferencias geométricas.
- Estudios de solubilidad y RMN, EPR, espectroscopia UV para el comportamiento de la solución.
Principales resultados:
- Se han sintetizado y aislado con éxito dos isómeros distintos de cobalto (SC-2 y HS-2) con una composición idéntica (Mo2Co (dpa) 4Br2).
- SC-2 exhibe una transición de giro de S=1/2 a S=3/2, mientras que HS-2 tiene un estado fundamental de S=3/2.
- Las diferencias geométricas, específicamente la longitud del enlace Co-Br, y las variaciones de solubilidad resultantes permitieron la separación física.
- Los isómeros se interconvierten lentamente en solución, con la polaridad del disolvente que influye en la forma predominante.
Conclusiones:
- Demostró la primera separación física de los isómeros del estado de espín del cobalto.
- Destacó el papel de las diferencias geométricas y de solubilidad en la separación de isómeros.
- Mostró poblaciones de isómeros dependientes de disolventes, ofreciendo nuevas vías para controlar el comportamiento de SCO.
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