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Bistabilidad y la transición de fase en el 1,3,2-dithiazolo[4,5-b]pyrazin-2-ylyl

Jaclyn L Brusso¹, Owen P Clements, Robert C Haddon

¹Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.

Journal of the American Chemical Society

|November 13, 2004

Resumen

El radical molecular 1,3,2-dithiazolo [4,5-b]pyrazin-2-yl (PDTA) muestra una bistabilidad magnética cerca de la temperatura ambiente. Su estructura cristalina cambia entre formas diamagnéticas y radicales a través de una transición de fase histérica.

Área de la Ciencia:

Ciencia de los materiales Ciencia de los materiales.
Química del estado sólido.
El magnetismo molecular es el magnetismo molecular.

Sus antecedentes:

Los radicales moleculares son de interés para aplicaciones electrónicas y magnéticas avanzadas.
La bistabilidad magnética en materiales orgánicos ofrece potencial para el almacenamiento de datos y la espintrónica.

Objetivo del estudio:

Para investigar la bistabilidad magnética del radical 1,3,2-dithiazolo[4,5-b]pyrazin-2-yl (PDTA) fue realizado un estudio.
Para aclarar los cambios estructurales asociados con la transición de fase.

Principales métodos:

Se empleó difracción de rayos X monocristalino para determinar las estructuras cristalinas de PDTA a diferentes temperaturas.
Se caracterizaron las propiedades magnéticas para identificar las temperaturas de transición de fase e histeresis.

Principales resultados:

PDTA exhibe bistabilidad magnética con distintas fases diamagnéticas de baja temperatura (LT-PDTA, S=0) y paramagnéticas de alta temperatura (HT-PDTA, S=1/2).
La transición de fase se produce a través de un bucle histérico con una temperatura de transición hacia abajo (TC↓) de 297(1) K y una temperatura de transición hacia arriba (TC↑) de 343(1) K.
El análisis estructural reveló que el LT-PDTA presenta pilas de pi-dimeros superpuestas, mientras que el HT-PDTA consiste en pilas de radicales pi deslizadas.

Conclusiones:

La bistabilidad magnética observada en PDTA está directamente relacionada con una transición de fase estructural.
El mecanismo de transición implica la ruptura cooperativa y la formación de interacciones S- - -N y una cascada de dominó de anillos apilados pi.
PDTA representa un material molecular prometedor para aplicaciones que requieren propiedades magnéticas conmutables.

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