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Acoplamiento de intercambio y bloqueo magnético en complejos de dilantanuro con puente de radicales de bipirimidilo
Selvan Demir1, Joseph M Zadrozny, Michael Nippe
1Department of Chemistry, University of California, Berkeley, 94720, United States.
Journal of the American Chemical Society
|November 1, 2012
Resumen
Los investigadores sintetizaron nuevos complejos de dilantanida con puente de radicales bipirimidil. Estos complejos exhiben un fuerte acoplamiento magnético y un comportamiento magnético de una sola molécula, con aplicaciones potenciales en el magnetismo molecular.
Área de la Ciencia:
- Coordinación Química de la Coordinación
- Ciencia de los materiales Ciencia de los materiales.
- El magnetismo es el magnetismo.
Sus antecedentes:
- Los complejos de lantánidos son de interés por sus propiedades magnéticas únicas.
- Los complejos de puentes de radicales ofrecen vías para fuertes interacciones de intercambio magnético.
- Los imanes de molécula única (SMM) son cruciales para el desarrollo de almacenamiento de datos de alta densidad y computación cuántica.
Objetivo del estudio:
- Para sintetizar y caracterizar nuevos complejos de dilantanuro con puente de radicales bipirimidil.
- Para investigar el acoplamiento de intercambio magnético entre los iones lantánidos y el radical bipirimidil.
- Para explorar el potencial de estos complejos como imanes de una sola molécula.
Principales métodos:
- Síntesis de tres nuevos complejos de dilantanuro: [(Cp*(2) Ln) (((2) (((μ-bpym (((•)))))) ((+)) (Ln = Gd, Tb, Dy).
- Mediciones de susceptibilidad magnética (dc) para sondear las interacciones y el comportamiento magnético.
- Análisis de datos magnéticos para determinar las constantes de acoplamiento y la dinámica de relajación.
Principales resultados:
- Se observó un fuerte acoplamiento de intercambio de lantánido ((III) -bipirimidil radical (Ln ((III) -bpym ((•-)) en todos los complejos sintetizados.
- El complejo gadolinio (III) mostró un acoplamiento antiferromagnético (J = -10 cm (-1)) con un estado de base S = 13/2.
- Los complejos de terbium (III) y disprosium (III) exhibieron un comportamiento magnético de una sola molécula con barreras de relajación significativas (U (eff) = 44 (eff) y 87.8 (eff) cm (-1), respectivamente).
- El complejo de disprosio (III) mostró divergencia enfriada por campo / enfriada por campo cero a 6,5 K e histeresis magnética, lo que indica una lenta relajación magnética.
Conclusiones:
- El radical bipirimidilo sirve como un ligando puente eficaz para mediar el intercambio magnético fuerte en los sistemas de dilantanuro.
- Los complejos sintetizados Tb (III) y Dy (III) demuestran prometedoras características magnéticas de una sola molécula debido a su gran anisotropía magnética.
- Estos hallazgos contribuyen al diseño de nuevos materiales magnéticos moleculares con aplicaciones potenciales en nanotecnología.
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