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Excepcional selectividad de intercambio iónico en un marco abierto flexible lantano (III) tetracisfosfonato

Monika Plabst¹, Lynne B McCusker, Thomas Bein

¹Department of Chemistry and Biochemistry and Center for NanoScience (CeNS), University of Munich (LMU), Butenandtstrausse 11, 81377 Munich, Germany.

Journal of the American Chemical Society

|November 20, 2009

Resumen

Este estudio muestra que el material flexible NaLa (H) intercambia selectivamente cationes monovalentes debido a la flexibilidad del marco. Sus canales se contraen al deshidratarse, adaptándose al tamaño de los iones huéspedes y a la entalpía de hidratación.

Área de la Ciencia:

Ciencia de los materiales Ciencia de los materiales.
Química Inorgánica La Química Inorgánica es la química inorgánica.
La cristalografía es una técnica de cristalografía.

Sus antecedentes:

Los materiales de marco abierto aniónicos ofrecen propiedades sintonizables para el intercambio iónico.
NaLa (NaLa) es un material recientemente descubierto con potencial para la unión selectiva de iones.

Objetivo del estudio:

Para aclarar la relación entre el comportamiento de intercambio iónico y la flexibilidad del marco en NaLa (H) (L).
Para investigar la selectividad de carga de NaLa (H) para varios cationes metálicos.

Principales métodos:

Experimentos de intercambio iónico con diferentes cationes metálicos.
Análisis elemental utilizando EDX y ICP-OES.
Difracción de rayos X y análisis termogravimétrico para estudios estructurales e hidratación.
Refinamiento de Rietveld para determinar las estructuras cristalinas.

Principales resultados:

NaLa (H) exhibe una excepcional selectividad para cationes monovalentes, rechazando iones de mayor valencia.
La flexibilidad del marco se confirmó a través de la hidratación / deshidratación reversible, causando una disminución del volumen celular del 15%.
El refinamiento de Rietveld reveló un mecanismo de reducción de canales específico para cationes que involucra cambios de coordinación de Na+.

Conclusiones:

La selectividad de carga de NaLa ((H ((4) L) se atribuye a la función específica del sitio de las adaptaciones de los huéspedes y la adaptación del marco.
La flexibilidad del marco permite que NaLa (((H ((4) L) se adapte específicamente al radio iónico y la entalpía de hidratación de los cationes invitados monovalentes.

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