Wachter, Wolfgang and Buchner, Richard and Hefter, Glenn (2006) Hydration of tetraphenylphosphonium and tetraphenylborate ions by dielectric relaxation spectroscopy. JOURNAL OF PHYSICAL CHEMISTRY B, 110 (10). pp. 5147-5154. ISSN 1520-6106,
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A systematic study of the dielectric relaxation spectra of aqueous solutions of NaBPh4 and Ph4PCl has been made at solute concentrations of 0.02 <= c/M <= 0.82 and 0.20, respectively, and over a wide range of frequencies (0.2 <= nu/GHz <= 89) at 25 degrees C. The spectra were best described by a superposition of four Debye processes, consisting of a very small ion-pair contribution with an average relaxation time of about 300 ps, a "slow" water relaxation at 17 ps, and two bulk-water relaxations at 8 ps and 0.25 ps, respectively. The slow-water process has been assigned to the presence of a sheath of water molecules surrounding BPh4- and Ph4P+, whose structure has been enhanced by its proximity to the bulky hydrophobic phenyl rings. A structure-making effect on the remaining solvent water can also be observed at low concentrations. More importantly, BPh4- and Ph4P+ show almost identical hydration characteristics, which provides indirect support for the use of the tetraphenylphosphonium tetraphenylborate reference electrolyte assumption in deriving single-ion thermodynamic properties.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | AQUEOUS-ELECTROLYTE SOLUTIONS; TEMPERATURE-DEPENDENCE; HEAT-CAPACITIES; SODIUM TETRAPHENYLBORATE; HYDROPHOBIC HYDRATION; SOLVENT RELAXATION; ORGANIC SOLVENTS; WATER-STRUCTURE; B-COEFFICIENTS; LIQUID WATER; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > PD Dr. Richard Buchner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 17 Feb 2021 12:39 |
| Last Modified: | 17 Feb 2021 12:39 |
| URI: | https://pred.uni-regensburg.de/id/eprint/34784 |
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