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Estructura molecular y electrónica de complejos dinucleares de uranio bis-μ-oxo con motivos estructurales de núcleo
Anna-Corina Schmidt1, Frank W Heinemann, Wayne W Lukens
1Inorganic Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander University of Erlangen-Nürnberg (FAU) , Egerlandstr. 1, 91058 Erlangen, Germany.
Journal of the American Chemical Society
|June 18, 2014
Resumen
Este estudio detalla la síntesis y caracterización de nuevos complejos de uranio oxo, revelando un fuerte acoplamiento antiferromagnético y la firma vibratoria del núcleo uranio-oxo.
Área de la Ciencia:
- Química organometálica Química orgánica de los metales.
- Química del Uranio La Química del Uranio
- Coordinación Química de la Coordinación
Sus antecedentes:
- Los complejos de uranio con enlaces múltiples son cruciales para comprender la reactividad del elemento f.
- La reactividad y las propiedades magnéticas de los complejos oxo de uranio no se comprenden completamente.
- Los complejos de uranio soportados por triazaciclononano (tacn) ofrecen una plataforma única para explorar la química del elemento f.
Objetivo del estudio:
- Para sintetizar y caracterizar nuevos complejos oxo de uranio (III), uranio (V) y uranio (VI).
- Para investigar el comportamiento redox de los complejos oxo de uranio dinuclear.
- Para aclarar las propiedades magnéticas y los motivos estructurales de estos complejos de uranio.
Principales métodos:
- Reacción de metatesis de enlaces múltiples de un precursor de U(III) con azido de mesitila y CO2.
- Síntesis y caracterización independiente de los intermediarios de imido y de óxo U(V) /U(V).
- Las titulaciones redox, UV/vis/NIR, la espectroscopia EPR, los estudios de magnetización SQUID y el etiquetado isotópico ((18) O).
Principales resultados:
- Formación de un complejo con puente dinuclear U(V) /U(V) bis(μ-oxo) a través de un intermediario de imido U(V).
- Demostración de un comportamiento rico en redox, que produce complejos mixtos-valentes U(IV) / U(V) y U(IV) / U(IV) tras la reducción.
- La oxidación conduce a complejos oxo U(VI) mononucleares; se observa un fuerte acoplamiento antiferromagnético entre los iones U(V).
- Asignación inequívoca de la firma vibratoria para el núcleo [U(μ-O) 2U] utilizando el etiquetado (18) O.
Conclusiones:
- Se ha establecido una nueva ruta sintética para los complejos de óxo de uranio.
- El estudio proporciona una visión profunda de las propiedades redox y magnéticas de las especies de uranio oxo.
- El análisis vibratorio confirma el motivo estructural del núcleo [U(μ-O) 2U], avanzando la comprensión de la química del uranio.
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