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Los patrones de iones sulfato en el agua a larga distancia.
Jeremy T O'Brien1, James S Prell, Matthew F Bush
1Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Journal of the American Chemical Society
|June 4, 2010
Resumen
El ion sulfato (SO4) influye en la estructura del agua mucho más allá de su vecindad inmediata. Este efecto de largo alcance, observado a través de la espectroscopia de fotodissociación infrarroja, es clave para comprender la serie Hofmeister.
Área de la Ciencia:
- Química Física es la química física.
- Física Química Física Química es la física de la química.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- La serie Hofmeister describe el ordenamiento de los iones en función de su efecto sobre la solubilidad de las proteínas.
- Los mecanismos moleculares precisos que impulsan los efectos de Hofmeister aún no se comprenden por completo.
- Investigar las interacciones entre iones y agua es crucial para dilucidar estos efectos.
Objetivo del estudio:
- Para investigar los orígenes químicos de la serie Hofmeister.
- Para comprender la influencia de largo alcance del ion sulfato en la estructura del agua.
Principales métodos:
- Se empleó la espectroscopia de fotodisociación por infrarrojos (IRPD).
- Se analizaron los espectros de IRPD de los grupos de iones sulfato-agua (SO(4) (((2-) (((H(2) O) ((n)) para diferentes números de hidratación (n).
Principales resultados:
- Una banda espectral distinta a ~3710 cm(-1) surgió para los cúmulos con más de 43 moléculas de agua (n > 43).
- Esta banda significa la presencia de grupos OH "libres" en las moléculas de agua de la capa externa, análogo al agua a granel.
- La ausencia de esta banda en grupos más pequeños (n <= 43) indica una transición estructural.
Conclusiones:
- El sulfato de dianio ejerce una influencia de largo alcance en la estructura del agua.
- Esta perturbación estructural extendida es un factor significativo que contribuye al observado comportamiento de Hofmeister del sulfato.
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