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Desenredar las propiedades mecanocrómicas de los polimorfos luminiscentes basados en benzotiadiazol a través de la
Marcelo Echeverri1, Constanza Ruiz1, Sergio Gámez-Valenzuela2
1Multifunctional and Supramolecular Materials Group, Materials Science Factory, Instituto de Ciencia de Materiales de Madrid-Consejo Superior de Investigaciones Científicas (ICMM-CSIC), Sor Juana Inés de la Cruz 3, Cantoblanco, Madrid 28049, Spain.
Journal of the American Chemical Society
|September 11, 2020
Resumen
Dos nuevos materiales orgánicos cambian de color cuando son estresados o expuestos a disolventes. Este comportamiento mecanocrómico está vinculado a su estructura cristalina e interacciones supramoleculares, ofreciendo ideas para diseñar materiales sensibles.
Área de la Ciencia:
- Ciencias de los materiales
- Química orgánica
- La cristalografía
Sus antecedentes:
- Los materiales luminóforos son cruciales para las aplicaciones optoelectrónicas.
- El polimorfismo en compuestos orgánicos puede conducir a propiedades físicas distintas.
- Los materiales sensibles a los estímulos ofrecen funcionalidades ajustables.
Objetivo del estudio:
- Para sintetizar y caracterizar dos nuevos polimorfos luminóforos de 4-bromo-7-(4-nonylphenyl) benzo[c][1,2,5]tiadiazol.
- Investigar las propiedades mecanocrómicas y la base estructural de estos polimorfos.
- Establecer las relaciones estructura-propiedad de los materiales orgánicos sensibles a los estímulos.
Principales métodos:
- Cristalografía de rayos X para la determinación de la estructura.
- Análisis de la topología del marco orgánico supramolecular (SOFT).
- Cálculos de la teoría funcional de la densidad dependiente del tiempo (TD-DFT).
- Experimentos de esfuerzo mecánico y exposición al vapor de disolventes.
Principales resultados:
- Se sintetizaron dos polimorfos (1α y 1β), que exhiben diferentes emisiones de color.
- Se observó una transformación de fase mecanocrómica reversible entre polimorfos en respuesta a la fuerza de cizallamiento y los vapores de disolvente.
- Los estudios SOFT revelaron redes topológicas distintas (mab y pcu) para cada polimorfo, correlacionadas con cambios estructurales debido a interacciones supramoleculares alteradas.
- TD-DFT racionalizó los cambios de color observados.
Conclusiones:
- El comportamiento mecanocrómico se atribuye a cambios reversibles en las interacciones supramoleculares y la topología cristalina.
- Se establecieron relaciones claras de propiedad SOFT, explicando el cambio de color sensible al estímulo.
- Los hallazgos proporcionan una base para el diseño de nuevos materiales orgánicos con propiedades intercambiables basadas en el diseño supramolecular.
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