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Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering
Published on: December 21, 2017
La protonación y el posterior enlace de hidrógeno intramolecular como método para controlar la estructura de la
Andrew P Monkman1, Lars-Olof Pålsson, Roger W T Higgins
1Department of Physics and the Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, United Kingdom. a.p.monkman@durham.ac.uk
Journal of the American Chemical Society
|May 23, 2002
Resumen
La protonación de grupos pirídicos en un polímero funcional induce la planaridad, extendiendo la conjugación pi y las propiedades ópticas de desplazamiento al rojo. Este cambio estructural en el poli-2,5-piridileno-co-1,4-[2,5-bis-2-etilhexiloxi]fenileno) es clave para ajustar los dispositivos optoelectrónicos.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Ciencia de los materiales Ciencia de los materiales.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- La protonación tiene un impacto significativo en las propiedades moleculares y poliméricas.
- La comprensión de los cambios estructurales es crucial para ajustar los materiales optoelectrónicos.
Objetivo del estudio:
- Investigar los efectos de la protonación en las propiedades estructurales y espectroscópicas de una molécula orgánica específica y su polímero correspondiente.
- Para dilucidar el mecanismo por el cual la protonación influye en la planaridad molecular y pi-conjugación.
Principales métodos:
- Análisis cristalográfico de rayos X de las formas protonadas y no protonadas de 1,4-dimetoxi-2,5-bis-2-piridil) benceno.
- Análisis espectroscópico (absorción y emisión ópticas) de la molécula y el polímero poli- (2,5-piridileno-co-1,4-[2,5-bis- 2-etilhexiloxi) fenileno) bajo condiciones ácidas.
- Estudios de electroluminiscencia de un dispositivo basado en polímeros.
Principales resultados:
- La protonación del 1,4-dimetoxi-2,5-bis(2-piridil) benceno con ácido tetrafluorobórico conduce a una sal de dication con un enlace de hidrógeno intramolecular significativo, causando una casi-planarización.
- La molécula planarizada y el polímero protonado exhiben grandes desplazamientos al rojo en los espectros de absorción óptica y de emisión.
- La protonación del polímero en solución y en películas induce desplazamientos al rojo espectrales similares, con emisiones que surgen tanto de sitios protonados como no protonados.
Conclusiones:
- La protonación, junto con el enlace de hidrógeno intramolecular, lleva al polímero a una conformación casi plana, extendiendo la conjugación pi.
- Este mecanismo proporciona una nueva ruta para ajustar los perfiles de absorción y emisión de polímeros conjugados.
- Los desplazamientos espectrales al rojo inducidos por la protonación también se observan en dispositivos electroluminiscentes basados en polímeros.
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