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Transferencia de electrones ultra rápida fotoinducida entre un donante encarcelado y un aceptador libre en solución
Mintu Porel1, Chi-Hung Chuang, Clemens Burda
1Department of Chemistry, University of Miami, Coral Gables, Florida 33124, USA.
Journal of the American Chemical Society
|August 31, 2012
Resumen
La transferencia de electrones fotoinducida entre la cumarina 153 y el viologen ocurre rápidamente dentro de un huésped ácido octa. La encapsulación acelera la dinámica y evita la relajación del disolvente, lo que demuestra un fuerte acoplamiento electrónico.
Área de la Ciencia:
- Se trata de una química supramolecular.
- La fotoquímica es la fotoquímica.
- Dinámica de transferencia de electrones Dinámica de transferencia de electrones
Sus antecedentes:
- La transferencia de electrones fotoinducida (PET) es crucial en los sistemas químicos y biológicos.
- Comprender el PET a través de las barreras moleculares es clave para diseñar sistemas fotosintéticos artificiales.
- La complejación anfitrión-invitado puede modular la cinética de transferencia de electrones.
Objetivo del estudio:
- Para investigar la dinámica de transferencia de electrones fotoinducida supramolecular entre la cumarina 153 (C153) y el 4,4'-dimetil viologen dicloruro (MV(2+)) dentro de un huésped de ácido octa (OA).
- Para dilucidar el efecto de la encapsulación en la cinética de transferencia de electrones y la dinámica de relajación.
- Explorar el papel de las interacciones huésped-huésped en la modulación de las vías de transferencia de electrones.
Principales métodos:
- Espectroscopia con resolución de tiempo de femtosegundos utilizando pulsos láser de 150 fs a 390 nm.
- Investigación de C153 y MV ((2+) dentro de las cápsulas de huésped OA.
- Análisis comparativo con dinámica de solución libre.
Principales resultados:
- Transferencia de electrones ultrarrápida de C153 fotoexcitado a MV2+) a través de la barrera molecular de OA.
- La transferencia de electrones se produjo dentro de 20 ps, a pesar de que el C153 estaba encapsulado.
- La vida útil del estado de transferencia de carga fue corta (724 ps) con una rápida transferencia hacia atrás (<1 ns), lo que indica un fuerte acoplamiento electrónico.
- La encapsulación aceleró la dinámica y suprimió la relajación del disolvente en comparación con la solución libre.
Conclusiones:
- La encapsulación supramolecular por OA altera significativamente la dinámica de transferencia de electrones inducida por la foto.
- Las interacciones huésped-huésped facilitan la transferencia de electrones ultrarrápidos a través de barreras moleculares.
- El estudio demuestra el potencial de las moléculas huésped para controlar y mejorar los procesos de transferencia de electrones.
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