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Mezcla de acoplamiento π-π a través del espacio y a través del enlace en alambres moleculares de
Mateusz Wielopolski1, Agustín Molina-Ontoria, Christina Schubert
1Department of Chemistry and Pharmacy & Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany.
Journal of the American Chemical Society
|May 18, 2013
Resumen
Los nuevos conjugados ZnP-pCp-oPPV-C60 muestran una transferencia de carga eficiente mediada por puentes de paraciclofano-oligofenileno-vinileno. Los estudios dependientes de la temperatura revelan distintos mecanismos de baja y alta temperatura que influyen en la dinámica de transferencia de carga.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La fotoquímica es la fotoquímica.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- Las moléculas orgánicas conjugadas son cruciales para las aplicaciones optoelectrónicas.
- Comprender los mecanismos de transferencia de carga en sistemas moleculares complejos es esencial para diseñar dispositivos eficientes.
- Los puentes de paraciclofano-oligofenilenovileno (pCp-oPPV) ofrecen propiedades electrónicas únicas para mediar la transferencia de carga.
Objetivo del estudio:
- Para sintetizar y caracterizar nuevos conjugados ZnP-pCp-oPPV-C60 con diferentes longitudes de puente pCp-oPPV.
- Para investigar la dinámica de transferencia de carga iniciada por la excitación de C60 y ZnP.
- Para dilucidar los mecanismos de transferencia de carga dependientes de la temperatura y su dependencia de la distancia.
Principales métodos:
- Síntesis en varios pasos que incluye olefinación de Horner-Wadsworth-Emmons y reacciones de Heck.
- Modelado molecular para predecir las vías de transferencia de carga.
- Investigaciones fotofísicas, incluida la espectroscopia de estado estacionario y de resolución temporal.
- Experimentos de fluorescencia dependientes de la temperatura (273338 K).
Principales resultados:
- Síntesis exitosa de los conjugados ZnP-pCp-oPPV-C60 con uno, dos y tres pCps.
- El modelado molecular y los datos fotofísicos confirman la transferencia predominante de agujeros a través de puentes pCp-oPPV.
- La excitación de C60 conduce a la formación directa de ZnP-(pCp-oPPV)
- La excitación de ZnP da como resultado una transferencia de carga más lenta y la posterior evolución de ZnP(•+) -pCp-oPPV-C60(•-).
- Se observaron dos dominios de temperatura: superintercambio a bajas temperaturas (<30 °C) y tasas crecientes a altas temperaturas (>30 °C).
- Se observó una fuerte dependencia de distancia para puentes más cortos (1, 2) y una débil dependencia para puentes más largos (2, 3).
Conclusiones:
- Los puentes pCp-oPPV median efectivamente la transferencia de carga en los conjugados ZnP-pCp-oPPV-C60.
- El mecanismo de transferencia de carga está influenciado por la fuente de excitación y la temperatura.
- La temperatura juega un papel crítico en la dinámica de transferencia de carga, con distintos regímenes de baja y alta temperatura.
- La dependencia de distancia observada proporciona información sobre el acoplamiento electrónico a través de los puentes, crucial para el diseño de la electrónica molecular.
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