Observation of Three Behaviors in Confined Liquid Water within a Nanopool Hosting Proton-Transfer Reactions

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• 作者：Abderrazzak Douhal ; Gonzalo Angulo ; Michal Gil ; Juan Á ; ngel Organero ; Mikel Sanz ; Laura Tormo
• 刊名：Journal of Physical Chemistry B
• 出版年：2007
• 出版时间：May 17, 2007
• 年：2007
• 卷：111
• 期：19
• 页码：5487 - 5493
• 全文大小：234K
• 年卷期：v.111,no.19(May 17, 2007)
• ISSN：1520-5207

文摘

In this contribution, we report on studies of rotational and diffusional dynamics of 7-hydroxyquinoline (7HQ)within a reverse micelle (RM) containing different amounts of water. Analyzed in terms of the wobbling-in-a-cone model, the data reveal structural and dynamical properties of the nanopool. We clearly observedthree regions in the behavior of confined water molecules within the RM hosting a double proton-transferreaction between the probe and water. This observation remarkably reproduces the change of calculated waterdensity within this life-mimicking medium. The number of water molecules per AOT head in the transitionregions changes from 2 to 5, the latter being very near to the full solvation number (6) of the RM heads.Moreover, the H-bonds breaking and making within the RM to give new structures of the probe stronglyaffect the environment fluidization in different extents, reflected in different relaxation times of these structures;however, they are of similar sizes. We discuss the role of RM confinement and the proton-transfer dynamicson the behavior of water and their relationships to the packing of water molecules in the studied range ofconcentrations.