La transferencia de carga mediada por agua y la localización de electrones en un complejo bipiramidal trigonal con
Emily Hruska1, Quansong Zhu1, Somnath Biswas1
1Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
Journal of the American Chemical Society
|March 13, 2024
Resumen
Los factores ambientales como la temperatura y los disolventes influyen en los estados de espín de los imanes moleculares. Este estudio revela cómo la transferencia de carga y la deslocalización de electrones controlan estas transiciones de espín, impactando las propiedades moleculares.
Área de la Ciencia:
- Química de coordinación
- Ciencias de los materiales
- Espectroscopia
Sus antecedentes:
- Los paramagnetos moleculares con puentes de cianuro exhiben comportamientos electrónicos complejos.
- Comprender los efectos ambientales en las transiciones de espín es crucial para la electrónica molecular.
- La deslocalización y localización de la carga influyen en las propiedades magnéticas y electrónicas.
Objetivo del estudio:
- Investigar el impacto de la temperatura y el entorno químico en un paramagnético molecular pentanuclear.
- Elucidar los mecanismos de transferencia de carga y las transiciones de espín en respuesta a estímulos externos.
- Para correlacionar las observaciones espectroscópicas con los cálculos teóricos para una comprensión completa.
Principales métodos:
- Espectroscopia de fotoemisión de rayos X (NAP-XPS) de presión cercana al ambiente específica para el elemento y el estado de oxidación para detectar la transferencia de carga.
- Espectroscopia vibratoria no lineal de segundo orden (espectroscopia vibratoria de generación de suma de frecuencias, SFG-VS) para detectar cambios de simetría.
- Cálculos de la Teoría Funcional de la Densidad (DFT) para apoyar los hallazgos experimentales.
Principales resultados:
- Los cambios de temperatura inducen la transferencia de carga de metal a metal (MMCT) entre los centros de cobalto y hierro.
- La presencia de disolvente (enlace H) conduce a la localización de la carga (estado de espín bajo de clase I de Robin-Day).
- La eliminación del disolvente promueve la deslocalización de la carga (estado de alto espín de clase II / III de Robin-Day) y MMCT.
- Se observó una conmutación reversible del momento dipolo, análoga a los multiferroicos moleculares.
Conclusiones:
- El entorno químico y la solvación juegan un papel crítico en el control de las transiciones de carga y espín.
- El grupo molecular exhibe un cambio reversible entre estados electrónicos localizados y deslocalizados.
- Los hallazgos ponen de relieve el potencial de tales complejos para aplicaciones en interruptores moleculares y materiales multiferroicos.
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