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El espectro infrarrojo de la matriz de neones de WH(6): una estructura de prisma trigonal distorsionada
1Department of Chemistry, University of Virginia, P.O. Box 400319, Charlottesville, Virginia 22904-4319, USA.
Journal of the American Chemical Society
|May 16, 2002
Resumen
Los investigadores sintetizaron hexahidruro de tungsteno (WH6) a través de la ablación láser y el aislamiento de la matriz de neón. El análisis espectroscópico y los cálculos de DFT confirmaron su estructura de prisma trigonal distorsionada, desafiando las suposiciones anteriores.
Área de la Ciencia:
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- Química cuántica es la química cuántica.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- Los hidritos de tungsteno son de interés debido a su enlace único y sus potenciales aplicaciones catalíticas.
- Estudios teóricos previos predijeron varias estructuras para los hidritos de tungsteno, pero la verificación experimental sigue siendo limitada.
- El aislamiento de matriz de neón es una técnica poderosa para estabilizar especies reactivas y estudiar sus propiedades a bajas temperaturas.
Objetivo del estudio:
- Para sintetizar y caracterizar el hexahidruro de tungsteno (WH6) utilizando métodos experimentales.
- Para aclarar la estructura molecular y las propiedades vibratorias de WH6.
- Para comparar los hallazgos experimentales con las predicciones teóricas de la Teoría Funcional de Densidad (DFT).
Principales métodos:
- Ablación láser de átomos de tungsteno (W) seguido de co-condensación con hidrógeno molecular (H2) en exceso de gas de neón (Ne) a temperaturas criogénicas.
- Espectroscopia infrarroja (IR) para identificar y analizar los modos de vibración de los productos de hidruro de tungsteno formados.
- Cálculos de la Teoría Funcional de Densidad (DFT) para predecir y asignar las frecuencias vibratorias y la estructura molecular de WH6.
Principales resultados:
- Se observó la formación de varios hidritos de tungsteno, incluidos WH, WH2, WH3, WH4 y WH6.
- El recocido promovió la formación de WH6, mientras que la fotólisis condujo a su disminución, lo que permitió la asignación espectral.
- Se asignaron seis bandas de absorción infrarroja distintas a WH6, mostrando una excelente concordancia con los modos de estiramiento y flexión / deformación W-H calculados por DFT.
Conclusiones:
- Los resultados experimentales apoyan fuertemente la estructura de prisma trigonal distorsionada predicha por DFT para WH6.
- Esta estructura se desvía significativamente de una geometría octaédrica, proporcionando información crucial sobre el enlace del hidruro de tungsteno.
- El estudio valida con éxito las predicciones teóricas a través de técnicas experimentales de aislamiento de matriz y técnicas espectroscópicas.
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