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Examen de los efectos de la variación del ligando en la estructura electrónica de las especies de uranio bis (imido)
John J Kiernicki1, Maryline G Ferrier2, Juan S Lezama Pacheco3
1H.C. Brown Laboratory, Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States.
Journal of the American Chemical Society
|October 13, 2016
Resumen
Los complejos de uranio altamente reducidos activan la arylazida y el diazeno, formando especies de uranio trans-bis-imido. La modificación y oxidación de ligandos revelan diversos estados de oxidación del uranio y estructuras electrónicas, confirmadas por espectroscopia y cristalografía.
Área de la Ciencia:
- Química organometálica
- Química del uranio
- Diseño del ligando
Sus antecedentes:
- Los complejos de uranio con ligandos redox activos ofrecen una reactividad única.
- La activación de pequeñas moléculas que contienen nitrógeno es crucial en la catálisis y la síntesis.
Objetivo del estudio:
- Investigar la activación de las arilazidas y los diagenos por complejos de uranio reducido.
- Explorar las estructuras electrónicas y los estados de oxidación de las especies de uranio resultantes.
- Caracterizar los nuevos complejos de uranio-imido.
Principales métodos:
- Síntesis de complejos de uranio con ligandos de piridina.
- Reacciones con arylazidas y diagenos.
- Caracterización espectroscópica (NMR, UV-Vis y XAS).
- Es una cristalografía de rayos X.
Principales resultados:
- Los complejos de uranio (IV) reducen fácilmente los arylazidos a las especies trans-bis (imido) de uranio (V).
- La escisión del diazeno es selectiva para complejos específicos de uranio.
- Las modificaciones de ligandos y la oxidación conducen a especies de uranio V y VI con estructuras electrónicas distintas.
- Se aislaron y caracterizaron los complejos catiónicos de uranio.
Conclusiones:
- Los ligandos de piridina ((diimina) redox-activos permiten una reactividad diversa en los complejos de uranio.
- Los ligandos trianiónicos facilitan la reducción de los enlaces N3R y N=N.
- El ajuste de las propiedades electrónicas de los complejos de uranio a través del diseño de ligandos y la oxidación es posible.
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