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Fotoquímica del 2-naftóilo azido. Un estudio espectroscópico y computacional ultrarrápido con resolución de tiempo
Jacek Kubicki1, Yunlong Zhang, Shubham Vyas
1Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland.
Journal of the American Chemical Society
|May 10, 2011
Resumen
La espectroscopia de femtosegundos revela la fotoquímica del 2-naftóilo azido en disolventes. El decaimiento en estado excitado implica el cruce intersistémico, la formación de nitreno e isocyanato, influenciado por la polaridad del disolvente.
Área de la Ciencia:
- La fotoquímica es la fotoquímica.
- La espectroscopia es una técnica de espectroscopia.
- Química computacional es la química computacional.
Sus antecedentes:
- El 2-naftóil azido es una molécula clave en la fotoquímica.
- Comprender la dinámica de su estado excitado es crucial para elucidar la vía de reacción.
Objetivo del estudio:
- Para investigar la fotoquímica del 2-naftóilo azido en varios disolventes.
- Para dilucidar los mecanismos de desintegración del estado excitado utilizando espectroscopia con resolución temporal y métodos computacionales.
Principales métodos:
- Espectroscopia de absorción transitoria con resolución de tiempo de femtosegundos con detección de vis IR y UV.
- Estudios realizados en disolventes polares y no polares.
- Estudios computacionales que incluyen cálculos de la diferencia de densidad de electrones.
Principales resultados:
- Formación y desintegración observadas del primer estado excitado singlet (S(1) en diferentes disolventes.
- Se han identificado tres vías de desintegración: cruce intersistémico, formación de nitreno en solitario y formación de isocyanato.
- Se encontró que la vida útil del estado S(1) disminuye con el aumento de la polaridad del disolvente; la formación de nitreno está vinculada a estados excitados de singlet más altos.
Conclusiones:
- La polaridad del disolvente tiene un impacto significativo en la vida útil del estado excitado y en las vías de reacción del 2-naftóilo azido.
- La formación de nitreno puede ocurrir tanto en el estado relajado S(1) como en los estados excitados singlet superiores (S(n)).
- La conversión interna y la fluorescencia son canales de descomposición ineficientes para el 2-naftóilo azido.
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