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El polimorfismo y la transformación estructural inducida térmicamente en los polímeros de coordinación
Ryohei Akiyoshi1, Honoka Motokawa1, Asuka Nishibe1
1Department of Chemistry, School of Science, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan.
Inorganic chemistry
|September 2, 2025
Resumen
Se estudiaron tres polimorfos de coordinación semiconductores. El tratamiento térmico indujo una transformación estructural en KGF-79, creando una estructura polar con actividad de generación de segundo armónico y fotoconductividad.
Área de la Ciencia:
- Ciencias de los materiales
- Química del estado sólido
- La cristalografía
Sus antecedentes:
- Los polímeros de coordinación semiconductores ofrecen propiedades electrónicas y ópticas ajustables.
- El polimorfismo en [Cd(2-SNPh) 2) n, un polímero de coordinación de cadmio ((II) tiolato, influye en las características estructurales y funcionales.
- Comprender las relaciones estructura-propiedad es crucial para el desarrollo de materiales avanzados.
Objetivo del estudio:
- Investigar la diversidad estructural y las propiedades de tres polimorfos de un polímero de coordinación de cadmio-tiolato, [Cd2-SNPh]n.
- Elucidar el mecanismo de la transformación estructural inducida térmicamente y su impacto en las propiedades del material.
- Explorar el comportamiento fotoconductor y los mecanismos de transporte de carga en estos materiales.
Principales métodos:
- Análisis estructural de rayos X de un solo cristal para determinar la disposición atómica de KGF-51 y KGF-71.
- Análisis de difracción de electrones de microcristales para caracterizar la estructura tridimensional del KGF-79.
- Mediciones de conductividad de microondas con resolución de tiempo para evaluar la fotoconductividad.
- Los cálculos de los primeros principios para comprender los mecanismos de transporte de cargas.
Principales resultados:
- KGF-51 exhibe una estructura de cadena de escalera de un solo hilo en 1D.
- KGF-71 muestra una estructura de cadena de doble cadena 1D estabilizada por las interacciones S·S.
- El tratamiento térmico de KGF-51 y KGF-71 produce KGF-79, una estructura de cadena tridimensional con interacciones S·S mejoradas.
- KGF-79 muestra una transición de la estructura no polar a la polar, lo que resulta en la actividad de segunda generación armónica (SHG).
- Los tres polimorfos demuestran fotoconductividad atribuida al transporte de carga a lo largo de cadenas (-Cd-S-) n a través de saltos.
Conclusiones:
- El estudio revela tres polimorfas distintas de un polímero de coordinación de cadmio-tiolato con dimensiones y motivos estructurales variables.
- La transformación inducida térmicamente y irreversible conduce a una estructura polar (KGF-79) con propiedades emergentes de SHG.
- Las cadenas (-Cd-S-) n inorgánicas son vías clave para el transporte de cargas, lo que permite la fotoconductividad en todos los polimorfos a través de un mecanismo de salto.
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