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La biestabilidad tautomérica de valencia basada en moléculas sincronizada con una fase de transición macroscópica de
Daisuke Kiriya1, Ho-Chol Chang, Susumu Kitagawa
1Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
Journal of the American Chemical Society
|March 28, 2008
Resumen
Este estudio revela el cambio molecular sincronizado y las transiciones de fusión de cristales en complejos de cobalto. Las cadenas alcóxicas facilitan esta sincronicidad, permitiendo la bistabilidad combinada molecular y macroscópica.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química Química es la química.
- La cristalografía es una técnica de cristalografía.
Sus antecedentes:
- El tautomerismo de valencia (VT) es un fenómeno que implica cambios reversibles en la distribución de electrones dentro de las moléculas.
- Las transiciones de fase macroscópicas, al igual que la fusión de cristales, implican cambios en el material a granel.
- La combinación de propiedades moleculares y macroscópicas es un objetivo clave en el diseño de materiales.
Objetivo del estudio:
- Investigar la bistabilidad sincrónica de la interconversión molecular tautomérica de valencia y las transiciones de fase de fusión de cristal.
- Para explorar el papel de las cadenas alcóxicas en los complejos cobalto-dioxoleno.
- Desarrollar estrategias para combinar biestabilidades basadas en moléculas y macroscópicas.
Principales métodos:
- Síntesis de nuevos complejos de cobalto-dioxoleno con diferentes longitudes de cadena alcoxi ([Co(CnOpy) 2 ((3,6-DTBQ) 2)).
- Caracterización utilizando técnicas para estudiar la interconversión molecular y las transiciones de fase.
- Análisis termodinámico para cuantificar los efectos de la sincronicidad.
Principales resultados:
- Se ha demostrado la bistabilidad sincrónica entre la interconversión VT molecular y la transición de fase de fusión de cristal.
- Histeresis térmica observada en la interconversión VT relacionada con la transición de fusión de cristales.
- Se encontró que la sincronicidad restringe la interconversión VT en ~ 50 K y acelera la transición de fusión de cristales en ~ 50 K.
- Sincronicidad atribuida a los efectos entálpicos/entrópicos de las cadenas alcoxi.
Conclusiones:
- Con éxito combinó biestabilidades basadas en moléculas y macroscópicas en complejos de cobalto.
- Mostró estrategias químicas y termodinámicas eficientes para el diseño de tales materiales.
- Destacó el papel crítico de la funcionalización de la cadena alkoxi en el control de la bistabilidad.
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