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Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
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La isomerización ultra rápida entre carbenos y carbenos.

Jin Wang1, Gotard Burdzinski, Jacek Kubicki

  • 1Department of Chemistry, Ohio State University, Columbus, Ohio 43210, USA.

Journal of the American Chemical Society
|March 28, 2008
PubMed
Resumen

Se estudió la fotoquímica de las aril diazo cetonas. Los estados excitados se descomponen rápidamente a través de múltiples vías, incluida la reorganización de Wolff y la formación de carbenos, revelando dinámicas de reacción complejas.

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Área de la Ciencia:

  • La fotoquímica es la fotoquímica.
  • Química orgánica es la química orgánica.
  • La espectroscopia es una técnica de espectroscopia.

Sus antecedentes:

  • Las aril diazocetonas son versátiles intermediarios sintéticos.
  • Comprender su dinámica de estado excitado es crucial para controlar los resultados de las reacciones.

Objetivo del estudio:

  • Para investigar la fotoquímica ultrarrápida de dos cetonas isoméricas de arilo diazo.
  • Para dilucidar las vías de descomposición competitivas de los estados excitados de diazo cetona.

Principales métodos:

  • Femtosegundo (fs) espectroscopia UV-vis con resolución de tiempo de femtosegundo (fs)
  • Espectroscopia de infrarrojos con resolución de tiempo en femtosegundos (fs).

Principales resultados:

  • Los estados excitados de ambos isómeros se descomponen en menos de 300 fs.
  • Se identificaron múltiples vías de descomposición, incluido el reordenamiento concertado de Wolff y la extrusión de nitrógeno.
  • Los rotómeros específicos exhiben vías distintas, como la migración de oxígeno o la formación directa de carbenos.
  • Se observó que los carbenos intermedios no reordenados se isomerizan en picosegundos (ps).

Conclusiones:

  • La fotoquímica de las aril diazo cetonas es muy compleja y ultra rápida.
  • Las vías de reacción son sensibles a la estereoquímica (configuración de los rotómeros).
  • Estos hallazgos proporcionan una visión crítica de los mecanismos de formación y reordenamiento de carbenos.