Quantification of the chiral recognition in electrochemically driven ion transfer across the interface water/chiral liquid

Abstract

The electrochemically driven transfer of the chiral anions of D -and L -tryptophan across the interface water/chiral liquid (D-or Lmenthol) is stereoselective, and it can be used to determine quantitatively the difference in Gibbs energies for the solvation of chiral ions in chiral liquids. The ion transfer can be achieved in a three-phase arrangement where a droplet of the chiral liquid containing decamethylferrocene as the electroactive redox probe is attached to a graphite electrode immersed in the aqueous solution containing the chiral ions. Ó

The determination of the standard Gibbs energies of ion transfer between water and heavy water by using the three-phase electrode approach

“…The recently developed technique to determine Gibbs energies of ion transfer using three-phase electrodes with organic solvent droplets immobilized on electrode surfaces proved to be useful for various solvent systems, e.g., water/nitrobenzene, water/dichloroethane, water/2-nitrophenyloctyl ether, water/n-octanol, water/menthol [7][8][9][10][11][12][13][14][15][16]. Since that technique provides rather low standard deviation data and offers an accuracy of the formal-potential measurement of 1 mV, we attempted to measure the small differences in Gibbs energies of ion transfer at the two interfaces H 2 Ojnitrobenzene and D 2 Ojnitrobenzene.…”

The determination of standard Gibbs energies of transfer of cations across the nitrobenzene|water interface using a three-phase electrode

“…The recent introduction of the three-phase electrode approach [12] has overcome some of the limitations of the four-electrode experiments, and led to significant progress in lipophilicity determinations of a large number of inorganic [13][14][15], and organic ions [13][14][15][16][17][18][19][20] across different liquidjliquid interfaces, such as waterjNB [12][13][14]16,17,19], waterjn-octanol [15,20], waterjmenthol [18], waterjDCE [12], and waterjnitrophenylnonyl ether [21].…”

“…When a droplet of this solution is attached to the working electrode and submerged in an aqueous electrolyte solution, the created charges in the organic liquid (due to the electrode reaction of the www.elsevier.com/locate/elecom electroactive compound) must be compensated by transfer of counter ions across the interface of the adjacent liquid phases in order to maintain the electroneutrality of the organic phase. We have shown that the standard potential of ion transfer across the liquidjliquid interface can be deduced from the formal potential of the voltammograms that portray the coupled electron transfer at the electrodejorganic solvent interface and ion transfer at the organic solventjwater solution interface [12][13][14][15][16][17][18][19][20]. A similar approach for monitoring the ion transfer across liquidjliquid interface was explored by Compton and co-workers [21][22][23][24][25], where the redox reactions of electroactive organic liquids have been studied in three-phase electrode arrangements.…”

Standard Gibbs energies of transfer of halogenate and pseudohalogenate ions, halogen substituted acetates, and cycloalkyl carboxylate anions at the water|nitrobenzene interface

“…they are more reliable. 2,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] The electrochemical technique introduced by one of us 24 and successfully applied to a number of systems [25][26][27][28][29] explores a so called '' three-phase electrode '' and conventional threeelectrode instrumentation. With this technique standard Gibbs energies for the water/nitrobenzene system can be determined in the range from À41 to +37 kJ mol À1 , 28 without coupling of solution equilibria.…”