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Un complejo de terbio N2(3-) con puente radical que exhibe histeresis magnética a 14 K
Jeffrey D Rinehart1, Ming Fang, William J Evans
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|August 16, 2011
Resumen
Los investigadores sintetizaron nuevos complejos de dilantanida que exhiben un comportamiento de imán de una sola molécula. El complejo de terbium es el imán molecular más duro hasta ahora, mostrando un acoplamiento de intercambio magnético efectivo para una relajación de temperatura más amplia.
Área de la Ciencia:
- Coordinación Química de la Coordinación
- Magnetoquímica es la Magnetoquímica.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- Los imanes de molécula única (SMM) son cruciales para el desarrollo de almacenamiento de datos de alta densidad y computación cuántica.
- Los iones lantánidos ofrecen una fuerte anisotropía magnética, una propiedad clave para los SMM.
- Los puentes radicales de nitrógeno (N) pueden mediar las interacciones de intercambio magnético entre los centros metálicos.
Objetivo del estudio:
- Para sintetizar y caracterizar los nuevos complejos de dilantánidos N(2)(3-) con puentes de radicales.
- Para investigar las propiedades magnéticas, particularmente el comportamiento SMM, de estos nuevos complejos.
- Explorar el papel del puente radical N(2)(3-) en la mediación del intercambio magnético y la mejora del rendimiento de SMM.
Principales métodos:
- Síntesis de tres complejos de dilantanuro: {[(Me(3) Si) (((2) N] (((2) THF) Ln} (((2) ((μ-η(2):η(2) -N(2)) (((-) (Ln = Tb, Ho, Er).
- Mediciones de propiedades magnéticas, incluida la susceptibilidad magnética y la histeresis magnética.
- Comparación con análogos sin puente radical para dilucidar el efecto del puente radical.
Principales resultados:
- Los tres complejos de dilantanuro sintetizados exhiben características del comportamiento del imán de una sola molécula.
- El congénero de terbio (Tb) muestra histeresis magnética a 14 K y una temperatura de bloqueo de 13.9 K (100 s).
- El puente radical N(2)(3-) media efectivamente el acoplamiento de intercambio magnético, impidiendo la relajación del campo cero y ampliando el rango de temperatura operativa.
Conclusiones:
- La combinación sinérgica de la anisotropía de Tb (III) y el acoplamiento de intercambio radical N (II) (III) produce el imán molecular más duro reportado hasta la fecha.
- El puente radical es esencial para lograr una relajación magnética lenta y robusta a temperaturas más altas.
- Estos hallazgos allanan el camino para diseñar materiales magnéticos moleculares avanzados con un rendimiento mejorado.
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