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Acoplamiento de intercambio ferromagnético fuerte y magnetismo de una sola molécula en complejos de dilantanuro
Lucy E Darago1, Monica D Boshart2, Brian D Nguyen2
1Department of Chemistry, University of California, Berkeley, California 94720, United States.
Journal of the American Chemical Society
|May 24, 2021
Resumen
Este estudio sintetizó nuevos compuestos 4d-4f que exhiben un fuerte intercambio ferromagnético entre los lantánidos y el molibdeno. Estos materiales muestran potencial para el desarrollo de imanes avanzados de una sola molécula y materiales magnéticos a granel.
Área de la Ciencia:
- Química inorgánica
- Ciencias de los materiales
- Magnetoquímica
Sus antecedentes:
- La investigación de nuevos compuestos heterometálicos 4d-4f es crucial para el avance del magnetismo molecular.
- La comprensión de las interacciones de intercambio entre metales en complejos polinucleares informa el diseño de materiales magnéticos.
Objetivo del estudio:
- Para sintetizar y caracterizar nuevos compuestos trinucleares 4d-4f.
- Investigar la estructura electrónica y las propiedades magnéticas, centrándose en la transferencia de carga de metal a metal y el intercambio magnético.
- Para explorar el potencial de estos compuestos como imanes de una sola molécula.
Principales métodos:
- Síntesis de compuestos trinucleares 4d-4f [Co(C5Me5) 2) [(C5Me5) 2Ln ((μ-S) 2Mo ((μ-S) 2Ln ((C5Me5) 2), 1-Ln (Ln = Y, Gd, Tb, Dy).
- Caracterización mediante espectroscopia de reflexión difusa UV-Vis-NIR, cálculos DFT, resonancia paramagnética de electrones (EPR) y mediciones de susceptibilidad magnética.
- Análisis de la susceptibilidad magnética para estudios de relajación magnética lenta.
Principales resultados:
- Los compuestos exhiben una transición de transferencia de carga de metal a metal de baja energía desde los orbitales Mo4d a Ln5d, mediada por el azufre.
- Se observaron una deslocalización significativa de electrones y fuertes interacciones de intercambio ferromagnético Ln-Mo.
- El compuesto 1-Gd muestra un estado básico S = 15/2 con una gran constante de intercambio Gd-Mo (J = +16.1(2) cm−1).
- Los compuestos 1-Tb y 1-Dy muestran una relajación magnética lenta, con 1-Dy exhibiendo la mayor barrera de relajación térmica reportada (Ueff = 68 cm−1) para un complejo que contiene 4d-metal.
Conclusiones:
- El estudio presenta una ruta generalizable para mejorar el intercambio magnético nd-4f.
- Estos hallazgos abren vías para diseñar nuevos imanes de una sola molécula nd-4f y materiales magnéticos a granel con propiedades a medida.
- El fuerte intercambio magnético observado y la lenta relajación resaltan el potencial de estos compuestos en el magnetismo molecular.
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