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Estructura y RMN multinuclear en estado sólido de un polímero de coordinación de cianuro de plomo y oro altamente
Michael J Katz1, Pedro M Aguiar, Raymond J Batchelor
1Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6.
Journal of the American Chemical Society
|March 16, 2006
Resumen
Este estudio sintetizó un nuevo polímero de coordinación, Pb(H2O) [Au(CN) 2], revelando su estructura de losa en 2D y propiedades ópticas únicas debido a la anisotropía centrada en el plomo. La deshidratación altera la estructura y la simetría, confirmada por la RMN en estado sólido.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química del estado sólido.
- La cristalografía es una técnica de cristalografía.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- Los polímeros de coordinación ofrecen estructuras y propiedades sintonizables.
- Se sabe que los cianuros de plomo (II) y oro (I) forman interesantes ensamblajes supramoleculares.
- Comprender las relaciones estructura-propiedad es crucial para el diseño de materiales.
Objetivo del estudio:
- Para sintetizar y caracterizar un nuevo polímero de coordinación que contiene plomo (II) y oro (I) cianuro.
- Para investigar los cambios estructurales tras la deshidratación.
- Para explorar las propiedades ópticas, específicamente la birefringencia, del material sintetizado.
Principales métodos:
- Síntesis de Pb (H2O) [Au (CN) ] 2 2 a través de la reacción de KAu (CN) 2 y Pb (NO3) 2 .
- Difracción de rayos X monocristalino para la determinación estructural de la forma hidratada.
- Espectroscopia de resonancia magnética nuclear (RMN) de estado sólido (13C, 15N, 1H, 207Pb) para las formas hidratadas y deshidratadas.
- Difracción de polvo de rayos X y mediciones de birefringencia.
Principales resultados:
- El compuesto hidratado Pb(H2O) [Au(CN) ]2 exhibe cadenas 1-D que forman losas 2-D con bicaped trigonal prismático plomo ((II) geometría.
- La deshidratación a 175 °C produce Pb microcristalino [Au (CN) ] 2 2 con simetría alterada y un entorno de plomo prismático cuadrado distorsionado propuesto.
- La forma hidratada muestra una birefringencia significativa (7.0 x 10^-2) atribuida a losas anisotrópicas 2-D y enlaces CN alineados.
Conclusiones:
- El polímero de coordinación Pb(H2O) [Au(CN) ]22 posee una estructura en capas 2D única con una notable anisotropía óptica.
- La deshidratación conduce a cambios estructurales y de simetría, evidenciados por la RMN en estado sólido.
- La gran birefringencia del material sugiere aplicaciones potenciales en materiales ópticos.
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