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Téteres de dicarboxilato poliinsaturados que conectan centros redox de dimolibdeno y centros cromóforos: espectros de
F Albert Cotton1, James P Donahue, Carlos A Murillo
1Department of Chemistry, Laboratory for Molecular Structure and Bonding, P.O. Box 30012, Texas A&M University, College Station, Texas 77842-3012, USA. cotton@tamu.edu
Journal of the American Chemical Society
|May 2, 2003
Resumen
El color de los compuestos de Mo(2) depende del enlace del dicarboxilato. Los enlaces insaturados causan colores intensos y una menor absorción de energía debido a las transiciones de transferencia de carga de metal a ligando.
Área de la Ciencia:
- Química Inorgánica La Química Inorgánica es la química inorgánica.
- Ciencia de los materiales Ciencia de los materiales.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- Los compuestos orgánicos metálicos exhiben diversas propiedades ópticas.
- El núcleo Mo(2) es un cromóforo conocido.
- Los enlaces de dicarboxilato pueden ajustar las propiedades del material.
Objetivo del estudio:
- Para investigar el impacto de los enlaces de dicarboxilato en los espectros de absorción de los compuestos [Mo(2) ((DAniF) ((3))) ((O(2) CXCO ((2)) ((Mo(2) ((DAniF)) ((3)).
- Para correlacionar las variaciones estructurales en el vinculante con los cambios de color observados y las transiciones electrónicas.
- Para dilucidar las excitaciones electrónicas responsables de los colores observados utilizando métodos computacionales.
Principales métodos:
- Se utilizó la espectroscopia de absorción para medir los espectros de los compuestos sintetizados.
- Se realizaron cálculos estáticos y dependientes del tiempo de la Teoría Funcional de Densidad (DFT).
- Análisis de las transiciones electrónicas y su relación con la estructura molecular.
Principales resultados:
- Los espectros de absorción mostraron una fuerte dependencia de la naturaleza química del enlazador dicarboxilato.
- Los enlaces de dicarboxilato insaturado dieron como resultado colores más intensos y menores absorciones de energía.
- Para los enlaces insaturados, las absorciones de energía más bajas se identificaron como transiciones de transferencia de carga de metal a ligando Mo(2)(4+) delta --> dicarboxilato pi.
- Los enlaces saturados llevaron a transiciones delta --> delta con cromóforos Mo(2)(4+) que no interactuaban.
Conclusiones:
- El enlazador dicarboxilato juega un papel crucial en la determinación del color y las propiedades electrónicas de estos compuestos Mo(2).
- La naturaleza del vinculante (saturado vs. insaturado) dicta el tipo de transición electrónica responsable del color observado.
- Los cálculos de DFT identificaron con éxito los orígenes electrónicos de las características espectrales observadas.
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