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La tautomerización de valencia dependiente del counterion de las sales de pirilio conjugadas con ferrocenilo
Mio Kondo1, Maai Uchikawa, Kosuke Namiki
1Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Journal of the American Chemical Society
|August 7, 2009
Resumen
La tautomerización de valencia en los nuevos compuestos de ferroceno-antraquinona está influenciada por los counteriones. El estudio revela que las interacciones electrostáticas entre la fracción [1-FcPyl]+ y los contraaniones como PF6(-) pueden afectar la aparición de la tautomerización de valencia (VT).
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- Química supramolecular de las moléculas.
Sus antecedentes:
- Los compuestos conjugados de donante-aceptor (DA) son cruciales para los materiales electrónicos avanzados.
- Las fracciones de ferroceno (Fc) y antraquinona (Aq) ofrecen propiedades electrónicas y redox únicas.
- Comprender las relaciones estructura-propiedad en los sistemas D-A es clave para el diseño de materiales.
Objetivo del estudio:
- Para sintetizar y caracterizar los nuevos derivados de ferroceno-etinilatraquinona.
- Investigar la influencia de los contraiones en las propiedades electrónicas y estructurales de estos compuestos.
- Para explorar el fenómeno de la tautomerización de valencia (VT) en sistemas de estado sólido D-A.
Principales métodos:
- Síntesis de 1-ferrocenilethynylanthraquinone (1-FcAq) y su producto de ciclocondensación, las sales de 2-ferroceniloxodihydrodibenzochromenylium ([1-FcPyl]+X-).
- Caracterización mediante métodos electroquímicos, espectroscopia UV-vis, análisis de rayos X monocristalino y cálculos TD-DFT.
- Espectroscopia de Mossbauer de temperatura variable, espectroscopia de infrarrojos y difracción de polvo de rayos X (XRPD) para estudiar VT y cambios estructurales.
Principales resultados:
- El sistema pi conjugado más grande en [1-FcPyl]+ reduce el nivel de LUMO en comparación con 1-FcAq.
- La tautomerización de valencia (VT) entre las especies Fe ((II) y Fe ((III) se observó en las sales TFSI ((-) y PF ((6)), pero no en BF ((4)).
- La identidad de la contraparte afecta significativamente los ángulos diédricos, la planaridad y las interacciones electrostáticas dentro de la estructura cristalina, lo que influye en VT.
Conclusiones:
- La ocurrencia de la tautomerización de valencia en las sales [1-FcPyl]+ es fuertemente dependiente de la naturaleza del contraanión.
- Las interacciones electrostáticas entre la fracción [1-FcPyl]+ y el contraanión juegan un papel crítico en la estabilización o desestabilización de las especies Fe (III).
- Los parámetros estructurales como los ángulos diédricos y la planaridad están modulados por conteriones, impactando las interacciones D-A y el comportamiento VT.
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