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Estructuras de canales de macrociclos hexaméricos autoensamblados en moléculas de varillas dobladas injertadas
Ho-Joong Kim1, Young-Hwan Jeong, Eunji Lee
1Center for Supramolecular Nano-Assembly and Department of Chemistry, Seoul National University, 599 Kwanak-ro, Seoul 151-747, Republic of Korea.
Journal of the American Chemical Society
|November 6, 2009
Resumen
Las moléculas de varillas dobladas con cadenas flexibles de oligoéter se autoensamblan en estructuras ordenadas. Las diferentes longitudes de las cadenas crean columnas 2D, capas de panales o estructuras en capas, revelando los principios de autoensamblaje molecular.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química supramolecular de las moléculas.
- Química orgánica es la química orgánica.
Sus antecedentes:
- Las moléculas de forma doblada ofrecen propiedades únicas de autoensamblaje en comparación con los análogos lineales.
- Las cadenas de oligoéteres pueden influir en el empaque molecular y las estructuras de granel.
Objetivo del estudio:
- Para sintetizar y caracterizar moléculas de varillas flexionadas injertadas internamente con diferentes longitudes de cadena de oligoéter.
- Investigar la influencia de la longitud de la cadena flexible y la ramificación en el comportamiento de autoensamblaje de las moléculas de varillas dobladas.
- Para dilucidar los modelos estructurales de los sistemas autoensamblados basados en datos experimentales.
Principales métodos:
- Síntesis de moléculas de nona-p-fenileno con forma doblada con cadenas de oligoéter.
- Caracterización mediante calorimetría de barrido diferencial (DSC), dispersiones de rayos X y microscopía electrónica de transmisión (TEM).
- Mediciones de densidad para apoyar el desarrollo de modelos estructurales.
Principales resultados:
- Todas las moléculas sintetizadas con forma de flexión exhibían estructuras de estado masivo ordenadas.
- Las cadenas cortas de oligoéteres llevaron a estructuras columnares en forma de canal 2D.
- Las longitudes intermedias de las cadenas dieron como resultado canales discretos que forman capas de panal.
- Las cadenas más largas indujeron estructuras en capas, mientras que las cadenas ramificadas formaron estructuras columnares 2D invertidas.
- Un modelo estructural propuso macrociclos hexaméricos formando columnas llenas de cadenas flexibles.
Conclusiones:
- La longitud y la ramificación de las cadenas de oligoéteres controlan críticamente el autoensamblaje de las moléculas de varillas dobladas.
- Los canales discretos de longitud definida son responsables de la formación de capas únicas de panal.
- Comprender estas relaciones estructura-propiedad es clave para diseñar nuevos materiales con autoensamblaje a medida.
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