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From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
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Modulación de la dinámica de rotación en sólidos cocristalinos halógenos
Shubha S Gunaga1, David L Bryce1
1Department of Chemistry and Biomolecular Sciences, Centre for Catalysis Research and Innovation, and Nexus for Quantum Technologies, University of Ottawa, 10 Marie Curie Private, Ottawa, Ontario K1N 6N5 Canada.
Journal of the American Chemical Society
|August 16, 2023
Resumen
Este estudio muestra cómo los enlaces halógenos pueden controlar la rotación del grupo metilo en los cristales. Al diseñar cocristales, los investigadores pueden ajustar la dinámica molecular para aplicaciones de ciencia de materiales.
Área de la Ciencia:
- Química del estado sólido
- Química supramolecular
- Ciencias de los materiales
Sus antecedentes:
- La dinámica molecular es crucial para la funcionalidad del material, la biomolécula y el catalizador.
- Las interacciones no covalentes, particularmente los enlaces halógenos (XB), ofrecen una ruta para controlar estas dinámicas.
Objetivo del estudio:
- Investigar sistemáticamente la modulación de la dinámica de rotación del grupo metilo utilizando enlaces halógenos.
- Diseñar y preparar nuevas arquitecturas cocristalinas con enlaces halógenos con tetrametilpirazina (TMP).
Principales métodos:
- Preparación de cocristales mediante métodos mecanoquímicos en fase gaseosa, en solución y en estado sólido.
- Difracción de rayos X monocristalino para el análisis estructural.
- Espectroscopia de resonancia magnética nuclear (RMN) de estado sólido de deuterio de temperatura variable para medir las barreras de rotación del metilo (Ea).
Principales resultados:
- Los enlaces halógenos, incluidos los de los donantes de bromo y cloro débil, actúan como elementos robustos de dirección de la estructura.
- Las barreras de rotación del metilo (Ea) en los cocristales de tetrametilpirazina oscilaron entre 3,75 y 7,08 kJ mol-1.
- Los factores estéricos (contactos cercanos carbono-carbono) y los factores electrónicos (resistencia al agujero sigma) rigen la dinámica observada.
Conclusiones:
- Los cocristales de diseño ofrecen una estrategia para modular la dinámica molecular mediante el control de la estequiometría y los contactos cercanos.
- Estos principios se pueden aplicar para afinar la dinámica en sistemas moleculares más complejos y grupos funcionales.
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