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Polimorfismo dinámico y reversible de sistemas cristalinos líquidos liotrópicos autoensamblados derivados de
Nozomi Saito1,2, Kiyoshi Kanie3, Masaki Matsubara3
1†Frontier Research Institute for Interdisciplinary Sciences, Tohoku University , 6-3 Aoba, Sendai 980-8578, Japan.
Journal of the American Chemical Society
|May 6, 2015
Resumen
Los oligómeros de etiinileliceno cíclicos sintéticos se autoensamblan en cristales líquidos dinámicos. Estas moléculas exhiben un polimorfismo reversible, en transición entre los estados ordenados de cristal líquido y gel.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- Ciencia de los materiales Ciencia de los materiales.
- Química orgánica es la química orgánica.
Sus antecedentes:
- Los cristales líquidos litotrópicos (CLL) son esenciales para los materiales avanzados.
- El control del polimorfismo en los sistemas autoensamblados es un desafío clave.
- Las moléculas sintéticas ofrecen propiedades sintonizables para el autoensamblaje.
Objetivo del estudio:
- Desarrollar un nuevo sistema de cristal líquido liotrópico autoensamblado (LLC).
- Investigar el polimorfismo dinámico y reversible en moléculas sintéticas.
- Para explorar las relaciones estructura-propiedad en oligómeros cíclicos de etinileliceno.
Principales métodos:
- Síntesis de los oligómeros cíclicos de etinileliceno (ciclobis[(M) -D-n]).
- Investigación de los cambios en la estructura molecular inducidos por la temperatura y los disolventes.
- Análisis del comportamiento de autoensamblaje y la formación de complejos con oligómeros acíclicos pseudoenantioméricos.
- Caracterización de las fases de cristal líquido y gel utilizando microscopía y otras técnicas.
Principales resultados:
- Los oligómeros cíclicos exhibieron transiciones estructurales entre las bobinas aleatorias y las hélices homo-dobles intramoleculares.
- La formación del complejo trimolecular (más de 10.000 Da) predominó sobre la formación del complejo bimolecular.
- El autoensamblaje en altas concentraciones produjo LLC de fibras alineadas anisotrópicamente, a diferencia de los sistemas acíclicos que forman geles.
- Se observó un polimorfismo termocrómico reversible entre las LLC y los geles turbios.
Conclusiones:
- Se desarrolló con éxito un nuevo sistema LLC autoensamblado con polimorfismo dinámico y reversible.
- La arquitectura molecular cíclica controla efectivamente la agregación desde el nivel molecular hasta el macroscópico.
- Este estudio presenta un ejemplo significativo de polimorfismo reversible en un sistema molecular totalmente sintético.
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