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Conjugados de varillas de carbohidratos: moléculas ternaras de rodilla-rodilla que forman complejas estructuras de
Bin Chen1, Ute Baumeister, Gerhard Pelzl
1Institute of Organic Chemistry, University Halle, Kurt-Mothes-Strasse 2, D-06120 Halle, Germany.
Journal of the American Chemical Society
|November 25, 2005
Resumen
Las nuevas moléculas en forma de T se autoorganizan en fases únicas de cristal líquido, incluyendo estructuras de red con subespacios periódicos tridimensionales. Estos hallazgos avanzan en la comprensión del autoensamblaje de materiales complejos y el comportamiento de fase.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química supramolecular de las moléculas.
- Los cristales líquidos son cristales líquidos.
Sus antecedentes:
- Las moléculas tribloqueantes polifílicas en forma de T combinan segmentos tipo barra, hidrófilos y lipofílicos.
- Comprender su autoorganización es clave para diseñar materiales avanzados.
Objetivo del estudio:
- Sintetiza nuevas moléculas tribloqueantes polifílicas en forma de T.
- Investigar su comportamiento cristalino líquido termotrópico y sus modos de autoorganización.
- Explorar la influencia de la estructura molecular en la formación de fases.
Principales métodos:
- Reacciones de acoplamiento cruzado catalizadas por paladio para la síntesis.
- Microscopía de luz polarizada, calorimetría de barrido diferencial (DSC) y dispersión de rayos X para la caracterización.
- Variación sistemática de las longitudes de los segmentos polares y lipofílicos.
Principales resultados:
- Descubrimiento de fases cristalinas líquidas inusuales, incluida la capa canalizada hexagonal (ChL ((hex)) y las redes parecidas a panales (cilindros cuadrados / pentagonales).
- Observación de una fase columnar hexagonal con organización tangencial del núcleo terfenilo.
- Inversión de la birefringencia en un compuesto debido a la reorientación del núcleo de terfenilo.
- Inducción de las fases lamelares con la adición de disolventes protóticos.
Conclusiones:
- La arquitectura molecular dicta una auto-organización compleja en fases únicas de cristal líquido periódico en 3D.
- Estos materiales exhiben diversos comportamientos de fase dependiendo de las longitudes de los segmentos y las interacciones con el disolvente.
- Los hallazgos ofrecen información sobre el diseño de materiales con estructuras supramoleculares a medida.
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