Journal article
Dynamics of Encapsulated Water inside Mo-132 Cavities
The journal of physical chemistry. B, Vol.115(19), pp.5980-5992
05/19/2011
DOI: 10.1021/jp110328z
PMID: 21510629
Abstract
The structure and dynamics of water confined inside a polyoxomolybdate molecular cluster [{(Mo)Mo5O21 (H2O)(6)}(12){Mo2O4(SO4)}(30)](72-) metal oxide nanocapsule have been studied by means of molecular dynamics simulations under ambient conditions. Our results are compared to experimental data and theoretical analyses done in reverse micelles, for several properties. We observe that the characteristic three-dimensional hydrogen bond network present in bulk water is distorted inside the cavity where water organizes instead in concentric layered structures. Hydrogen bonding, tetrahedral order, and orientational distribution analyses indicate that these layers are formed by water molecules hydrogen bonded with three other molecules of the same structure. The remaining hydrogen bond donor/acceptor site bridges different layers as well as the whole structure with the hydrophilic inner side of the cavity. The most stable configuration of the layers is thus that of a buckyball with 12 pentagons and a variable number of hexagons. The geometrical constraints make it so that the bridges between the layers display a significant degree of frustration. The main modes of motion at short times are correlated fluctuations of the entire system with a characteristic frequency. Switches of water molecules between layers are rare events, due to the stability of the layers. At long times, the system shows a power law decay (pink noise) in properties like the fluctuations in the number of molecules in the structures and the total dipole moment. Such behavior has been attributed to the complex relaxation of the hydrogen bond network, and the exponents found are close to those encountered in bulk water for the relaxation of the potential energy. Our results reveal the importance of the competition between the confinement and the long-range structure induced in this system by the hydrogen bond network.
Details
- Title: Subtitle
- Dynamics of Encapsulated Water inside Mo-132 Cavities
- Creators
- Miguel Garcia-Rates - Univ Rovira & Virgili, Dept Engn Quim, ETSEQ, Tarragona 43007, SpainPere Miro - Institut Català d'Investigació QuímicaJosep Maria Poblet - Univ Rovira & Virgili, Dept Quim Fis & Quim Inorgan, Tarragona 43007, SpainCarles Bo - Institut Català d'Investigació QuímicaJosep Bonet Avalos - Univ Rovira & Virgili, Dept Engn Quim, ETSEQ, Tarragona 43007, Spain
- Resource Type
- Journal article
- Publication Details
- The journal of physical chemistry. B, Vol.115(19), pp.5980-5992
- Publisher
- Amer Chemical Soc
- DOI
- 10.1021/jp110328z
- PMID
- 21510629
- ISSN
- 1520-6106
- eISSN
- 1520-5207
- Number of pages
- 13
- Grant note
- 2005SGR00715 / CIRIT of the Catalan Government URV/ICIQ2007 / Programa d'ajuts de Recerca Cooperativa CTQ2008-06469/PPQ; CTQ2008-06549-CO2-02/BQU; CSD2006-0003 / Ministerio de Ciencia e Innovacion of the Spanish Government; Spanish Government ICIQ Foundation; Foundation CELLEX
- Language
- English
- Date published
- 05/19/2011
- Academic Unit
- Chemistry
- Record Identifier
- 9984618521302771
Metrics
3 Record Views