Planar or Nonplanar:  What Is the Structure of Urea in Aqueous Solution?

A combined quantum chemical statistical mechanical method has been used to study the solvation of urea in water, with emphasis on the structure of urea. The model system consists of three parts:  a Hartree−Fock quantum chemical core, 99 water molecules described with a polarizable force−field, and a...

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Published inThe journal of physical chemistry. B Vol. 111; no. 39; pp. 11511 - 11515
Main Authors Hermida-Ramón, Jose Manuel, Öhrn, Anders, Karlström, Gunnar
Format Journal Article
LanguageEnglish
Published United States American Chemical Society 04.10.2007
Subjects
Chemical Sciences
Kemi
Natural Sciences
Naturvetenskap
Teoretisk kemi
Theoretical Chemistry
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Summary:A combined quantum chemical statistical mechanical method has been used to study the solvation of urea in water, with emphasis on the structure of urea. The model system consists of three parts:  a Hartree−Fock quantum chemical core, 99 water molecules described with a polarizable force−field, and a dielectric continuum. A free-energy profile along the transition of urea from planar to a nonplanar structure is calculated. This mode in aqueous solution is found to be floppy. That is, the structure of urea in water is not well-defined because the planar to nonplanar transition requires an energy of the order of the thermal energy at room temperature. We discuss the implications of this finding for simulation studies of urea in polar environments like water and proteins.
Bibliography:ark:/67375/TPS-HGBFMLTH-6
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SourceType-Scholarly Journals-1
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ISSN:1520-6106
1520-5207
1520-5207
DOI:10.1021/jp073579x