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Anillos de fenilo giratorios como un interruptor dependiente del invitado en estructuras bidimensionales

Christopher R Murdock¹, Nicholas W McNutt, David J Keffer

¹Department of Chemistry, ‡Department of Chemical and Biomolecular Engineering, and §Department of Materials Science and Engineering, University of Tennessee , Knoxville, Tennessee 37996-1600, United States.

Journal of the American Chemical Society

|December 20, 2013

Resumen

Las nuevas estructuras metal-orgánicas con nanotubos sintonizables exhiben transformaciones dinámicas. La rotación del anillo de fenilo ajusta el tamaño del tubo, controlado por las moléculas invitadas y la solvación, ofreciendo un nuevo método para el monitoreo del marco.

Área de la Ciencia:

Ciencia de los materiales Ciencia de los materiales.
La cristalografía es una técnica de cristalografía.
Química supramolecular de las moléculas.

Sus antecedentes:

Las estructuras metálicas orgánicas (MOF) son materiales cristalinos con diversas aplicaciones.
Los MOF anisotrópicos con porosidad ajustable son de gran interés para la investigación.
Comprender las transformaciones de estado sólido en MOF es crucial para su uso práctico.

Objetivo del estudio:

Para sintetizar y caracterizar nuevos marcos 2D metal-orgánico con 1D topología de nanotubos.
Para investigar las transformaciones de estado sólido de estos marcos en respuesta a la solvación.
Explorar el mecanismo de inclusión de moléculas invitadas y la respiración en el marco.

Principales métodos:

Síntesis de bis ((1,2,4-triazol) de cobre ((I) en las estructuras.
Difracción de rayos X monocristalino para el análisis estructural.
Difracción de rayos X en polvo (PXRD) y estado sólido (13)C polarización cruzada de ángulo mágico giratorio (CP-MAS) RMN para el monitoreo de transformaciones.
Simulaciones computacionales para comprender la dinámica de la energía.

Principales resultados:

Formación de estructuras 2D metal-orgánicas con topología de nanotubos 1D fundidos.
Observación de dos transformaciones distintas del estado sólido: expansión/contracción de la capa y rotación del anillo fenilo.
La rotación del anillo de fenilo permite un tamaño de tubo ajustable, lo que demuestra un efecto de "puerta".
La RMN de estado sólido (13) C CP-MAS monitorea directamente la rotación del fenilo y la respiración del marco, superando el rendimiento de PXRD.

Conclusiones:

Los MOFs sintetizados exhiben un notable comportamiento dinámico y porosidad sintonizable.
La rotación del anillo de fenilo es un mecanismo clave para controlar el acceso de las moléculas invitadas dentro de los nanotubos.
La RMN de estado sólido (13) C CP-MAS es una herramienta poderosa para caracterizar las transformaciones impulsadas por la respiración y la solvación del marco.

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