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Mejora significativa de las barreras energéticas en los imanes de una sola molécula de disprosio dinuclear a través
Fatemah Habib1, Gabriel Brunet, Veacheslav Vieru
1Chemistry Department, University of Ottawa , 10 Marie Curie, Ottawa, ON, K1N6N5, Canada.
Journal of the American Chemical Society
|August 23, 2013
Resumen
Los ligandos que retiran electrones mejoran significativamente las barreras de energía en los imanes de molécula única (SMM). Los ligandos fluorados condujeron a un aumento de siete veces, lo que demuestra una poderosa estrategia para el desarrollo de materiales magnéticos avanzados.
Área de la Ciencia:
- Coordinación Química de la Coordinación
- Ciencia de los materiales Ciencia de los materiales.
- El magnetismo cuántico es el magnetismo cuántico.
Sus antecedentes:
- Los imanes de una sola molécula (SMM) son materiales moleculares que exhiben una lenta relajación magnética.
- El control de la barrera energética (Ueff) es crucial para el rendimiento de SMM.
- El diseño de ligandos ofrece una vía prometedora para afinar las propiedades de SMM.
Objetivo del estudio:
- Investigar el impacto de los ligandos que extraen electrones en las barreras energéticas del disprosio dinuclear (III) SMMs.
- Para sintetizar y caracterizar nuevos SMM {Dy2} con ligandos terminales variables.
- Para establecer una relación estructura-propiedad entre la modificación del ligando y el comportamiento magnético.
Principales métodos:
- Síntesis de cinco nuevos SMM dinucleares {Dy2} fenoxo-puenteados.
- Caracterización estructural mediante difracción de rayos X. Caracterización estructural mediante difracción de rayos X.
- Mediciones de propiedades magnéticas, incluida la susceptibilidad a la corriente continua (dc) y a la corriente alterna (ac).
- Ab initio cálculos para determinar las estructuras electrónicas y las barreras energéticas.
Principales resultados:
- Mejora sistemática de la barrera energética anisotrópica con aumento del carácter de retirada de electrones de los ligandos terminales.
- Se observó un aumento de siete veces en la barrera energética para el complejo con un ligando de acetilacetonato fluorado (6).
- Los cálculos ab initio indicaron más tensores g axiales y una mayor energía de los dobles de Kramers excitados por primera vez en los complejos 4 y 6, correlacionándose con el aumento de las barreras de energía.
Conclusiones:
- Los ligandos de retirada de electrones son efectivos para aumentar significativamente las barreras de energía de {Dy2} SMM.
- La fluoración de los ligandos representa una estrategia potente para maximizar el rendimiento de SMM.
- El estudio proporciona información valiosa sobre el diseño de ligandos para el desarrollo de materiales magnéticos moleculares de alto rendimiento.
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