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Las vías de apagado de fluorescencia de punto cuántico con complejos Cr (III). la producción de NO fotosensibilizado

Daniel Neuman¹, Alexis D Ostrowski, Alexander A Mikhailovsky

¹Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106-9510, USA.

Journal of the American Chemical Society

|December 14, 2007

Resumen

Este estudio explora cómo los complejos de cromo (III) interactúan con los puntos cuánticos (QD). Los investigadores descubrieron que estos complejos pueden apagar la emisión de luz QD, con algunos que permiten la liberación de óxido nítrico fotosensibilizado.

Área de la Ciencia:

Ciencia de los materiales Ciencia de los materiales.
La fotoquímica es la fotoquímica.
Nanotecnología La nanotecnología es la nanotecnología.

Sus antecedentes:

El selenuro de cadmio soluble en agua/sulfuro de zinc (CdSe/ZnS) y los puntos cuánticos del núcleo/caparazón (QD) exhiben fotoluminiscencia (PL).
Los complejos de cromo (III), específicamente trans-Cr (Cyclam) Cl2+, trans-Cr (Cyclam) ONO2+ y trans-Cr (Cyclam) CN2+, se investigan para su interacción con los QD.

Objetivo del estudio:

Para investigar la perturbación de la fotoluminiscencia QD por complejos de cromo (III).
Evaluar los QD como antenas para la liberación fotosensibilizada de moléculas bioactivas, como el óxido nítrico (NO), de los centros de metales de transición.

Principales métodos:

Se utilizó la espectroscopia de fotoluminiscencia (PL) para observar el apagado de la emisión.
Se emplearon PL de resolución temporal y espectroscopia de absorción para estudiar la dinámica ultrarrápida.
Se exploraron los mecanismos de transferencia de energía de resonancia Förster (FRET) y de transferencia de carga.

Principales resultados:

trans-Cr ((ciclam) Cl2+ y trans-Cr ((ciclam) ONO) 2+ causaron el apagado dependiente de la concentración de la emisión del borde de banda QD, mientras que el trans-Cr ((ciclam) CN) 2+ tuvo un efecto mínimo.
El apagado por trans-Cr(ciclam) Cl2+ fue atenuado por KCl, lo que sugiere un ensamblaje electrostático entre los cationes Cr(III) y las superficies QD cargadas negativamente.
Se observó la liberación de NO fotosensibilizado con trans-Cr ((cyclam) ((ONO) 2+), un precursor conocido de NO, junto con el apagado de las emisiones de trampa de borde de banda y de desplazamiento al rojo.

Conclusiones:

El apagado PL de borde de banda se atribuye a FRET desde QDs hasta complejos de cromo ((III) en la superficie.
El apagado de la emisión de la trampa de baja energía se produce a través de una vía de transferencia de carga.
El estudio demuestra el potencial de los QD como antenas para aplicaciones de liberación fotosensibilizadas.

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