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Los conjuntos de cationes supramoleculares de hidrógeno enlazado (NH4+/NH2NH3+) en conductores moleculares y imanes
Tomoyuki Akutagawa1, Tatsuo Hasegawa, Takayoshi Nakamura
1Research Institute for Electronic Science, Hokkaido University, Sapporo 060-0812, Japan. takuta@imd.es.hokudai.ac.jp
Journal of the American Chemical Society
|July 26, 2002
Resumen
Este estudio explora nuevos conjuntos de cationes supramoleculares enlazados con hidrógeno utilizando amonio (NH4+) e hidrazinio (NH2-NH3+) con éteres de corona incorporados en sales eléctricamente conductoras de níquel bis (Ni) ([Ni (dmit)) 2). Estos conjuntos exhiben estructuras únicas y propiedades semiconductoras, con uno que muestra interacciones ferromagnéticas.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- Ciencia de los materiales Ciencia de los materiales.
- Química del estado sólido.
Sus antecedentes:
- Los complejos de metioleno metálico conductor de electricidad, como el níquel bis (((diotioleno) ([Ni ((dmit) 2), son conocidos por sus diversas propiedades electrónicas.
- Los ensamblajes supramoleculares ofrecen estructuras y funcionalidades sintonizables a través de interacciones no covalentes como el enlace de hidrógeno.
- Los éteres de la corona son macrociclos versátiles capaces de formar complejos con varios cationes, influyendo en el empaque y las propiedades del cristal.
Objetivo del estudio:
- Sintetizar y caracterizar nuevos conjuntos de cationes supramoleculares de amoníaco (NH4+) e hidrazinio (NH2-NH3+) enlazados con hidrógeno con diferentes éteres de corona ([12] corona-4, [15] corona-5, [18] corona-6).
- Incorporar estos conjuntos en sales eléctricamente conductoras [Ni(dmit) 2] e investigar sus propiedades estructurales y electrónicas.
- Explorar la influencia de las interacciones de éter catión-corona en las estructuras cristalinas resultantes y la conductividad.
Principales métodos:
- Síntesis de conjuntos de cationes supramoleculares que incluyen amonio/hidrazinio y éteres de corona.
- Incorporación de estos conjuntos en sales de [Ni(dmit) 2].
- Difracción de rayos X monocristalino para determinar las estructuras cristalinas y los arreglos supramoleculares.
- Mediciones de conductividad eléctrica para evaluar las propiedades semiconductoras.
- Análisis de las interacciones de enlace de hidrógeno (N-H···O) dentro de los conjuntos.
Principales resultados:
- Formación de estructuras piramidales y de canales iónicos con conjuntos de éter de corona de amonio, que exhiben ocupación de catión no estoiquiométrica y trastorno estático que conduce a electrones de conducción localizados.
- Identificación por primera vez de conjuntos de éter de hidrazinio-corona de estado sólido con estructuras sándwich y sándwich.
- Detección de la interacción ferromagnética (temperatura de Weiss = +1 K) en el (NH2-NH3+) 2
- Isomorfismo entre los cristales (NH2-NH3+) 0,8([18]corona-6) [Ni(dmit) 2) 2 y (NH4+) 0,76([18]corona-6) [Ni(dmit) 2) 2, lo que demuestra la adaptabilidad estructural de [18]corona-6.
Conclusiones:
- Los conjuntos de cationes supramoleculares de amoníaco e hidrazinio enlazados con hidrógeno con éteres de corona pueden ser efectivamente incorporados a las sales [Ni ((dmit) 2], dando lugar a diversas estructuras cristalinas.
- El tamaño y la flexibilidad de los éteres de corona, junto con las interacciones de éter catión-corona, influyen significativamente en el empaque, la estequiometría y las propiedades electrónicas de los materiales resultantes.
- Estos nuevos conjuntos representan una plataforma prometedora para el desarrollo de nuevos materiales funcionales con propiedades electrónicas y magnéticas sintonizables.
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