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Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
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La vía fotoquímica hacia el hierro octaédrico. Procesos primarios y rendimientos cuánticos de la espectroscopia
Hendrik Vennekate1, Dirk Schwarzer, Joel Torres-Alacan
1Max-Planck-Institut für biophysikalische Chemie , Am Fassberg 11, 37077 Göttingen, Germany.
Journal of the American Chemical Society
|June 21, 2014
Resumen
Los estudios fotoquímicos revelan que la luz UV, no la luz visible, genera nitruro de hierro de alta valencia a partir de [Cyclam-ac) Fe (III) (N3)) en solución. La fotooxidación compite con la fotorreducción y la escisión de enlaces en femtosegundos.
Área de la Ciencia:
- La fotoquímica es la fotoquímica.
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- El catión complejo [cyclam-ac) Fe (III) (N3)) es un precursor fotoquímico conocido.
- Estudios anteriores utilizaron matrices sólidas bajo condiciones criogénicas.
Objetivo del estudio:
- Investigar los eventos fotoquímicos primarios del catión complejo en solución líquida a temperatura ambiente.
- Compara el comportamiento de la solución con los experimentos previos de criomatriz.
Principales métodos:
- Espectroscopia de infrarrojo medio (fs-MIR) con resolución de tiempo de cinco segundos.
- Espectroscopia infrarroja con transformación de Fourier por escaneo paso a paso. espectroscopia infrarroja.
- Excitación de longitud de onda variable. excitación de longitud de onda variable.
Principales resultados:
- La excitación por luz visible (banda LMCT) conduce a la disociación de azido redox-neutral, no a la fotooxidación.
- La excitación de la luz UV forma el producto de nitruro de hierro de alta valencia.
- La fotooxidación compite con la escisión fotorreductiva de enlaces Fe-N y la ruptura de enlaces N-N en femtosegundos.
- La recombinación geminada ocurre en una escala de tiempo de picosegundos.
Conclusiones:
- La fotoquímica de la solución difiere significativamente de los resultados de la criomatriz.
- La fotólisis UV es eficaz para generar nitruro de hierro de alta valencia, pero requiere una cuidadosa consideración de las vías de competencia.
- El rendimiento cuántico primario para la fotooxidación aumenta con la energía del fotón.
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