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Complejos de lantánidos heteropolinucleares para la conversión ascendente de sensibilización cooperativa en el agua
Léna Godec1, Richard C Knighton1,2, Nadège Hamon3
1Equipe de Synthèse pour l'Analyse (SynPA), IPHC, UMR 7178, CNRS/Université de Strasbourg, ECPM, 25 Rue Becquerel, 67087 Strasbourg Cedex, France.
Journal of the American Chemical Society
|August 13, 2025
Resumen
Este estudio sintetizó un nuevo ligando tritópico (L2) para la complejación de lantánidos (Ln), lo que permite una conversión ascendente de sensibilización cooperativa (UC) con una mayor eficiencia al calentarse. El complejo tetranuclear mostró la UC más eficiente, logrando un rendimiento cuántico de 9,0 × 10-7.
Área de la Ciencia:
- Química de coordinación
- Química supramolecular
- La fotofísica
Sus antecedentes:
- Los complejos de lantánidos (Ln) son cruciales para diversas aplicaciones, incluida la luminiscencia y la catálisis.
- El desarrollo de ligandos que controlan la coordinación Ln y las propiedades fotofísicas es esencial para los materiales avanzados.
- Los procesos de conversión ascendente (UC) en complejos Ln ofrecen capacidades únicas de recolección y emisión de luz.
Objetivo del estudio:
- Sintetizar y caracterizar un nuevo ligando tritópico (L2) capaz de unirse a múltiples iones lantánidos.
- Investigar la química de coordinación y las propiedades fotofísicas de los complejos lantánidos con L2.
- Explorar el potencial de estos complejos en los procesos cooperativos de sensibilización y conversión.
Principales métodos:
- Síntesis del ligando tritópico L2 basado en andamios de triazaciclonanos (tacn) trifuncionalizados y un vinculante de trietilenglicol.
- Coordinación de varios iones lantánidos (Eu, Tb, Yb, Lu) con el ligando L2.
- Caracterización mediante RMN y espectroscopias fotoluminiscentes.
- Investigación de las propiedades de la UC tras la excitación Yb a 980 nm.
- Modelado de la Teoría Funcional de Densidad (DFT) para comprender las interacciones de enlace.
Principales resultados:
- Síntesis exitosa del ligando tritópico L2 y formación de complejos de lantánidos mono, di, tri y tetranucleares.
- Demostración de la conversión hacia arriba de la sensibilización cooperativa (UC) en complejos Yb-Tb, con emisión visible de Tb.
- Se ha observado un aumento significativo (aprox. 10^3) en la eficiencia de la UC al calentarse debido a la codificación Ln.
- Identificación del complejo tetranuclear [TbYb(TbYbL2) ] como el emisor UC más eficiente.
- Se logró un rendimiento cuántico UC de 9.0 × 10^-7 a la excitación de 980 nm.
Conclusiones:
- El nuevo ligando tritópico L2 controla efectivamente el ensamblaje de los complejos lantánidos polinucleares.
- En estos complejos, especialmente en las especies tetranucleares, se consigue una conversión ascendente de sensibilización cooperativa.
- El tratamiento térmico mejora la eficiencia de la UC promoviendo la redistribución de iones lantánidos dentro del ligando.
- Estos hallazgos allanan el camino para el desarrollo de materiales luminiscentes avanzados basados en complejos de coordinación de lantánidos.
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