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Macrociclos de forma persistente con unidades de terpiridina: síntesis, caracterización y estructura en el cristal
Christian Grave1, Dieter Lentz, Andreas Schäfer
1Institut für Chemie, Freie Universität Berlin, Takustrasse 3, D-14195 Berlin, Germany.
Journal of the American Chemical Society
|June 5, 2003
Resumen
Los investigadores sintetizaron macrociclos grandes y de forma persistente con unidades de terpiridina de hasta 2 nm de ancho utilizando reacciones de acoplamiento cruzado. Estas moléculas, con cadenas laterales flexibles, se caracterizaron por varios métodos espectroscópicos y de difracción.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- Síntesis orgánica La síntesis orgánica.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- Los macrociclos de forma persistente son bloques de construcción cruciales en la química supramolecular.
- Las unidades de terpiridina son valiosos ligandos para la construcción de estructuras orgánicas metálicas y polímeros de coordinación.
- Controlar el tamaño y las propiedades del macrociclo es esencial para el diseño de materiales avanzados.
Objetivo del estudio:
- Para sintetizar nuevos macrociclos de forma persistente que incorporan una o dos unidades de terpiridina.
- Para lograr macrociclos con grandes diámetros interiores (hasta 2 nm).
- Para investigar la influencia de las cadenas laterales en la solubilidad, el procesamiento y el envasado de cristales.
Principales métodos:
- Reacciones de acoplamiento cruzado catalizadas por metales de transición para ensamblaje de macrociclos.
- Decoración de los precursores con cadenas laterales flexibles de hexiloxi o hexiloximetilo.
- Caracterización mediante espectrometría de masas MALDI-TOF, espectroscopia de RMN 2D y difracción de rayos X de un solo cristal.
- Microscopía de túnel de barrido (STM) para estudios de interfaz.
Principales resultados:
- Síntesis exitosa de macrociclos con una o dos unidades de terpiridina y diámetros interiores de hasta 2 nm.
- Los rendimientos totales oscilaron entre el 8% y el 27%, con cantidades preparadas de hasta 290 mg.
- La ingeniería de la cadena lateral mejoró la solubilidad y el procesamiento.
- El análisis del empaque de cristal reveló la dependencia del número y la longitud de la cadena lateral.
- La fisisorción ordenada de un macrociclo en la interfaz solución-HOPG se observó a través de STM.
Conclusiones:
- El estudio demuestra una vía sintética viable para grandes macrociclos que contienen terpiridina, de forma persistente.
- Las cadenas laterales flexibles son efectivas para mejorar la procesabilidad y controlar la estructura de estado sólido.
- Los macrociclos sintetizados muestran potencial para aplicaciones en química supramolecular y ciencia de los materiales.
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