Characteristics of the 'Hypercoordination' of hydroxide (OH−) in water: A comparative study of HF/MM and B3LYP/MM MD simulations
| Autor: | Anan Tongraar, Pathumwadee Yotmanee, Apirak Payaka |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Aqueous solution
Hydrogen Chemistry Hydrogen bond Analytical chemistry Solvation chemistry.chemical_element Condensed Matter Physics Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials chemistry.chemical_compound Solvation shell Computational chemistry Phase (matter) Materials Chemistry Molecule Hydroxide Physical and Theoretical Chemistry Spectroscopy |
| Zdroj: | Journal of Molecular Liquids. 188:89-95 |
| ISSN: | 0167-7322 |
| DOI: | 10.1016/j.molliq.2013.09.028 |
| Popis: | The solvation structure and dynamics of hydroxide (OH−) in water have been studied by means of two combined QM/MM MD simulations, namely HF/MM and B3LYP/MM, in which the central OH− and its surrounding water molecules were treated at HF and B3LYP levels of accuracy, respectively, using a 6-311++G(d,p) basis set. On the basis of both the HF/MM and B3LYP/MM MD simulations, it is observed that the hydrogen bonds (HBs) between OH− and its first-shell waters are quite strong, i.e., compared to that of bulk water. Nevertheless, the solvation shell of OH− is flexible, in which the first-shell waters can be either “loosely” or “tightly” bound to OH− (with either a short-lived or long-lived exchange period). In this respect, the oxygen site in OH− prefers to be dynamically hypercoordinated by the surrounding waters, i.e., by accepting four or five HBs, while the OH− hydrogen is found to donate a HB, but only transiently. This observed phenomenon strongly supports the concept that the mechanism of OH− transport in aqueous solution relies on the dynamical hypercoordination scenario. Comparing the HF/MM and B3LYP/MM results, the observed differences are discussed with respect to the quality of the HF and B3LYP methods in describing such condensed phase system. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect