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La organización supramolecular de los sexitiofenos alfa, alfa'-disubstituidos por las alfa
A P H J Schenning1, A F M Kilbinger, F Biscarini
1Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Journal of the American Chemical Society
|February 14, 2002
Resumen
Los derivados quirales del sexitiofeno se autoensamblan en agregados ordenados en disolución y en estado sólido. Estas moléculas exhiben un autoensamblaje cooperativo y un comportamiento cristalino líquido termotrópico, con formas quirales dirigiendo a sus contrapartes achirales.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- Materiales orgánicos Ciencia de la materia orgánica.
- Química Física es la química física.
Sus antecedentes:
- Los oligotiofenos son semiconductores orgánicos clave con propiedades electrónicas sintonizables.
- Las cadenas laterales quirales pueden inducir comportamientos específicos de autoensamblaje en moléculas orgánicas.
- Comprender el autoensamblaje es crucial para el diseño de materiales orgánicos funcionales.
Objetivo del estudio:
- Para investigar el autoensamblaje de nuevos derivados quirales y achirales de sexitiofeno.
- Para caracterizar la formación de agregados quirales en diversos entornos.
- Explorar los efectos cooperativos y las propiedades cristalinas líquidas de estos sistemas.
Principales métodos:
- Espectroscopia UV / vis, fluorescencia y dicroísmo circular (CD). espectroscopía UV / vis, fluorescencia y dicroísmo circular (CD).
- Espectroscopia de polarización circular de la luminiscencia (CPL, por sus siglas en inglés).
- Espectrometría de masas, microscopía de fuerza atómica (AFM).
Principales resultados:
- Los derivados del sexitiofeno forman agregados quirales en disolventes polares y películas sólidas.
- La agregación es dependiente de la temperatura, con distintos puntos de fusión y sin intermedios desordenados.
- Las moléculas quirales actúan como "sargentos" para dirigir el ensamblaje de las moléculas achirales en agregados mixtos, demostrando su cooperatividad.
- Comportamiento cristalino líquido termotrópico observado entre 180-200°C.
- AFM revela la autoorganización en estructuras similares a las fibras quirales en el estado sólido.
Conclusiones:
- Las cadenas quirales de penta ((etilenglicol) inducen efectivamente el autoensamblaje quiral en los sistemas de sexitiofeno.
- Se observan efectos cooperativos en agregados mixtos, destacando el reconocimiento molecular.
- Estos compuestos poseen potencial para aplicaciones en electrónica orgánica y materiales quirales.
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