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Los catalizadores organocalcógenos dendrímeros para la activación del peróxido de hidrógeno: mejora de la actividad
C Francavilla1, M D Drake, F V Bright
1Departments of Chemistry and Medicinal Chemistry, State University of New York at Buffalo, Buffalo, New York 14260, USA.
Journal of the American Chemical Society
|March 29, 2001
Resumen
Los fenilselenuros y los feniltellururos dendrímeros catalizan la oxidación del bromuro utilizando el peróxido de hidrógeno. Los fenilselenuros exhiben efectos catalíticos cooperativos, logrando altos números de rotación (> 60,000) para reacciones de oxidación eficientes.
Área de la Ciencia:
- Química supramolecular de las moléculas.
- Química organometálica Química orgánica de los metales.
- La catálisis es la catálisis.
Sus antecedentes:
- Los dendrímeros ofrecen arquitecturas únicas a nanoescala para el diseño de materiales funcionales.
- Los grupos fenilcalcogénicos (sulfuros, selenuros, telururos) pueden ser incorporados en los dendrímeros.
- La catálisis que involucra a los calogenuros es un área activa de investigación.
Objetivo del estudio:
- Para sintetizar nuevos polifenilsulfuros dendrímeros, -selenidos y -telluridos.
- Para investigar su actividad catalítica en la oxidación del bromuro utilizando peróxido de hidrógeno.
- Explorar las relaciones estructura-actividad y los efectos cooperativos en la catálisis.
Principales métodos:
- Síntesis de dendrímeros con espaciadores propiloxi y términos fenilcalcogénicos.
- Oxidación catalítica del bromuro en sistemas de dos fases utilizando peróxido de hidrógeno.
- Estudios cinéticos para determinar las velocidades de reacción y los números de rotación.
- Modificación sistemática de la estructura de los dendrímeros para probar la cooperatividad.
Principales resultados:
- Se lograron altos rendimientos de polifenilsulfuros dendrímeros, selenidos y tellururos.
- Los selenuros y tellururos dendrímeros catalizaban efectivamente la oxidación del bromuro a especies positivas de bromo.
- Los fenilsulfuros no mostraron actividad catalítica.
- Las tasas catalíticas de los tellururos siguieron las contribuciones estadísticas.
- Los fenilselenuros exhibieron efectos cooperativos, excediendo las predicciones estadísticas.
- Un dendrimero con 12 grupos de fenilselenos demostró un alto número de rotación (>60.000).
Conclusiones:
- Los fenilselenuros y los telururos dendrímeros son catalizadores eficientes para la oxidación del bromuro.
- La cooperación entre los grupos de fenilselenos mejora la actividad catalítica.
- Estos dendrímeros representan catalizadores prometedores para reacciones de oxidación con alta eficiencia y volumen de negocios.
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