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Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Un complejo de carbenos-carbenos en equilibrio de equilibrio
Robert A Moss1, Lei Wang, Christina M Odorisio
1Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, USA. moss@rutchem.rutgers.edu
Journal of the American Chemical Society
|August 5, 2010
Resumen
El fenilclorocarbeno forma complejos de tipo pi estables con el 1,3,5-trimetoxibenceno. Estos complejos de carbenos existen en equilibrio con el carbeno, con parámetros termodinámicos medidos que indican estabilidad.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La fotoquímica es la fotoquímica.
- Química supramolecular de las moléculas.
Sus antecedentes:
- Los carbenos son intermediarios altamente reactivos cruciales en la síntesis orgánica.
- Comprender las interacciones de los carbenos con los sistemas aromáticos es clave para controlar la reactividad.
- La fenilclorodiazirina sirve como un precursor para generar fenilclorocarbeno.
Objetivo del estudio:
- Investigar la formación y la estabilidad de los complejos de tipo pi entre el fenilclorocarbeno y el 1,3,5-trimetoxibenceno.
- Para cuantificar el equilibrio y los parámetros termodinámicos que rigen esta interacción carbeno-areno.
Principales métodos:
- Generación de fenilclorocarbeno a través de la fotólisis de flash láser de la fenilclorodiazirina.
- Caracterización espectroscópica (UV-vis) de los complejos carbeno-areno.
- Análisis computacional para apoyar los hallazgos experimentales.
- Determinación de las constantes de equilibrio y parámetros termodinámicos a través de estudios dependientes de la temperatura.
Principales resultados:
- Se formaron complejos de tipo pi altamente estables entre el fenilclorocarbeno y el 1,3,5-trimetoxibenceno en pentano.
- El carbeno y sus complejos se encontraron en equilibrio.
- La constante de equilibrio (K = 1264 M−1) y los parámetros termodinámicos (ΔH° = -7.1 kcal/mol, ΔS° = -10.2 eu, ΔG° = -4.1 kcal/mol) se determinaron a 294 K. Los parámetros termodinámicos (ΔH° = -7.1 kcal/mol, ΔS° = -10.2 eu, ΔG° = -4.1 kcal/mol) también se determinaron a 294 K.
Conclusiones:
- El fenilclorocarbeno forma fácilmente complejos pi estables con compuestos aromáticos ricos en electrones como el 1,3,5-trimetoxibenceno.
- Los datos de equilibrio y termodinámicos proporcionan información cuantitativa sobre la estabilidad y la naturaleza de estas interacciones carbeno-areno.
- Este estudio pone de relieve el potencial para estabilizar las especies de carbenos reactivos a través de la complicación.
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