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Reacciones de acoplamiento oligómero-oligómero versus oligómero-monómero C(2) -C(2)' en el crecimiento de
J C Lacroix1, F Maurel, P C Lacaze
1Institut de Topologie et de Dynamique des Systèmes, Université de Paris 7-Denis Diderot, associé au CNRS (UPRES-A 7086), 1 rue Guy de la Brosse, 75005 Paris, France.
Journal of the American Chemical Society
|July 18, 2001
Resumen
Se modeló la oxidación electroquímica de los oligopirroles. Se observaron distancias de acoplamiento más cortas y una dimerización más rápida en el agua para oligopiroles más largos, lo que influye en los mecanismos de formación de polímeros.
Área de la Ciencia:
- La electroquímica es electroquímica.
- Química computacional es la química computacional.
- La ciencia de los polímeros es la ciencia de los polímeros.
Sus antecedentes:
- Los oligopirroles son polímeros conductores muy importantes.
- Comprender su acoplamiento radical-catión es clave para controlar la polimerización.
Objetivo del estudio:
- Para modelar las reacciones de acoplamiento de los radicales oligopirrol-cationes C(2) -C(2) '.
- Investigar la influencia de la longitud del oligómero y los efectos del disolvente en los mecanismos de acoplamiento.
Principales métodos:
- Se emplearon cálculos de estado de transición.
- La oxidación electroquímica generó radicales-cationes.
- Los efectos del disolvente se incorporaron al modelado.
Principales resultados:
- La distancia de acoplamiento en los estados de transición disminuye con el aumento de la longitud del oligómero.
- Las tasas de dimerización disminuyen en la fase gaseosa pero aumentan en el agua con la longitud del oligómero.
- El acoplamiento oligómero-monómero es más rápido que el acoplamiento oligómero-oligómero para la formación de cuaterpirrol y sexipirrol.
Conclusiones:
- La polaridad del disolvente tiene un impacto significativo en las tasas de dimerización de cationes radicales de oligopirrol.
- El mecanismo para la formación de oligopirroles largos puede implicar el acoplamiento de unidades dication-neutral.
- Los hallazgos proporcionan información sobre el control de la electropolimerización de los derivados del pirrol.
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