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Polyoxotungstate en forma de rueda [Cu20Cl ((OH) 24 ((H2O) 12 ((P8W48O184) ]25- Los macroaniones forman una
Guang Liu1, Tianbo Liu, Sib Sankar Mal
1Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
Journal of the American Chemical Society
|August 3, 2006
Resumen
Los investigadores descubrieron que los estados polioxotungados hidrófilos se autoensamblan en estructuras huecas y esféricas de tipo "berry". Este hallazgo sugiere un fenómeno general para los macroiones, no específico para los polioxomolibdatos.
Área de la Ciencia:
- Química Inorgánica La química inorgánica es la química inorgánica.
- Química supramolecular de las moléculas.
- Ciencia de los materiales Ciencia de los materiales.
Sus antecedentes:
- Los polioxometalatos (POM) son grupos inorgánicos versátiles con diversas estructuras y propiedades.
- El autoensamblaje de macroiones en arquitecturas complejas es un área clave en la química supramolecular.
- Los estudios previos sobre la formación de la mora se limitaron a las polyoxomolybdates.
Objetivo del estudio:
- Para investigar el comportamiento de autoensamblaje de un nuevo estado polioxotungado hidrófilo, [Cu20Cl(OH) 24(H2O) 12(P8W48O184) ]25- ({Cu20P8W48}).
- Para explorar la formación de estructuras tipo arándanos con este polioxometalato que no contiene molibdeno.
- Para estudiar las propiedades electroforéticas de estas estructuras macroiónicas autoensambladas.
Principales métodos:
- La dispersión dinámica de la luz (DLS, por sus siglas en inglés)
- La dispersión estática de la luz (SLS, por sus siglas en inglés)
- Análisis del potencial Zeta.
- Microscopía electrónica de barrido (SEM, por sus siglas en inglés)
Principales resultados:
- El estado polioxotungado {Cu20P8W48} se autoensambla en estructuras esféricas huecas y esféricas de una sola capa en soluciones acuosas.
- Este es el primer informe de formación de moras negras para un polioxometalato que no contiene molibdeno.
- La formación de Blackberry fue independiente de la concentración macroiónica y la temperatura.
- Los macroiones {Cu20P8W48} son los más pequeños aún observados para exhibir este comportamiento de autoensamblaje (radios equivalentes < 2 nm).
- Los estudios electroforéticos revelaron que la densidad de carga dentro de la estructura de la mora es menor que la de los macroiones libres, lo que sugiere una asociación conterional.
Conclusiones:
- La formación de estructuras tipo Blackberry es probablemente un fenómeno general para los macroiones hidrófilos en disolventes polares.
- El sistema {Cu20P8W48} proporciona información sobre la transición de iones simples a macroiones en soluciones diluidas.
- Los counteriones monovalentes juegan un papel crucial en el autoensamblaje de los macroiones, mediando potencialmente las fuerzas atractivas para la formación de la mora.
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