Agieienko, Vira and Horinek, Dominik and Buchner, Richard (2017) Hydration and self-aggregation of a neutral cosolute from dielectric relaxation spectroscopy and MD simulations: the case of 1,3-dimethylurea. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 19 (1). pp. 219-230. ISSN 1463-9076, 1463-9084
Full text not available from this repository. (Request a copy)Abstract
The influence of the amphiphile 1,3-dimethylurea (1,3-DMU) on the dynamic properties of water was studied using dielectric relaxation spectroscopy. The experiment provided evidence for substantial retardation of water reorientation in the hydration shell of 1,3-DMU, leading to a separate slow-water relaxation in addition to contributions from bulk-like and fast water as well as from the solute. From the amplitudes of the resolved water modes effective hydration numbers were calculated, showing that each 1,3-DMU molecule effectively freezes the reorientation of 1-2 water molecules. Additionally, a significant amount of solvent molecules, decreasing from similar to 39 at infinite dilution to similar to 3 close to the solubility limit, is retarded by a factor of similar to 1.4 to 2.3, depending on concentration. The marked increase of the solute amplitude indicates pronounced parallel dipole alignment between 1,3-DMU and its strongly bound H2O molecules. Molecular dynamics (MD) simulations of selected solutions revealed a notable slowdown of water rotation for those solvent molecules surrounding the methyl groups of 1,3-DMU and strong binding of similar to 2H(2)O by the hydrophilic carbonyl group, corroborating thus the experimental results. Additionally, the simulations revealed 1,3-DMU self-aggregates of substantial lifetime.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PARTICLE MESH EWALD; MOLECULAR-DYNAMICS; AQUEOUS-SOLUTIONS; ELECTROLYTE-SOLUTIONS; WATER REORIENTATION; UREA SOLUTIONS; ALPHA-CHYMOTRYPSINOGEN; HYDROPHOBIC HYDRATION; ALKYLUREA SOLUTIONS; FORCE-FIELD; |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 14 Dec 2018 13:01 |
| Last Modified: | 26 Feb 2019 08:05 |
| URI: | https://pred.uni-regensburg.de/id/eprint/570 |
Actions (login required)
 |
View Item |
