Gulaboski, Rubin and Mirceski, Valentin and Scholz, Fritz (2002) An electrochemical method for determination of the standard Gibbs energy of anion transfer between water and n-octanol. Electrochemistry Communications, 4 (4). pp. 277-283. ISSN 13882481
Preview |
Text
__ugd.edu.mk_private_UserFiles_rubin.gulaboski_Desktop_GULABOSKI-MY pdf PUBLICATIONS_octanol-Electrochem Commun 2002.pdf Download (217kB) | Preview |
Abstract
The transfer of the ions Cl�, Br�, I�, ClO�
4 , SCN�, NO�
3 , BF�
4 , and ðC6H5Þ4B� across the waterjn-octanol (WjOC) liquid interface
was studied and the standard Gibbs energies of ion transfer were determined. The ion transfer was achieved by oxidation of
decamethylferrocene dissolved in a droplet of n-octanol that was attached to a graphite electrode immersed in the aqueous solutions
of the respective alkali salts of the anions. The electrode reaction can be described by the equation: dmfcðOCÞ þ X�
ðWÞ¢dmfcþ
ðOCÞ þ
X�
ðOCÞ þ e�, where X� is the transferred anion. Square-wave voltammetry at this three-phase arrangement was utilised to determine
the formal potential of the decamethylferrocene/decamethylferrocenium ðdmfc=dmfcþÞ couple under the condition of ion transfer
across the waterjn-octanol interface. For calibration the standard Gibbs energies of ion transfer have been extrapolated to octanol
from the series of known data for methanol, ethanol, n-propanol, and n-butanol. All these data are consistent and the experimental
dependence of the formal potentials on the standard Gibbs energies is as predicted by theory. The validity of data is further
supported by calculations of Gibbs energies of ion transfer using the Born theory. Until now it was not possible to perform
electrochemical measurements at the waterjn-octanol interface because in the conventional four-electrode cells this interface cannot
be polarised. With the new method it is now for the first time possible to determine the Gibbs energies of transfer of ions across the
waterjn-octanol interface. These values are of very wide use for assessing the lipophilicity of compounds in chemistry, medicine, and
pharmacology.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ion transfer, octanol, lipophilicity, voltammetry, drug design |
| Subjects: | Medical and Health Sciences > Basic medicine Natural sciences > Biological sciences Natural sciences > Chemical sciences Natural sciences > Physical sciences |
| Divisions: | Faculty of Agriculture |
| Depositing User: | Rubin Gulaboski |
| Date Deposited: | 31 Oct 2012 13:15 |
| Last Modified: | 01 Nov 2012 10:07 |
| URI: | https://eprints.ugd.edu.mk/id/eprint/163 |
Actions (login required)
 |
View Item |