Estimation of parameters characterizing the adsorption of sodium, potassium, and rubidium cryptates at the mercury electrode/solution interface

Abstract

The adsorption of complexes formed by sodium, potassium, and rubidium cations with macrobicyclic ligand (kryptofix 222 with C 18 H 36 N 2 O 6 composition) is studied as a function of the ligand concentration on a stationary mercury drop in 0.1 M solutions of corresponding sulfates and chlorides by using the differential capacitance technique. Based on the model of two parallel capacitors supplemented by the Frumkin isotherm, the adsorption parameters of studied cryptates are estimated by using the regression analysis technique. Differential capacitance curves calculated with the parameters found are compared with experimental data. The comparison of the found adsorption parameters makes it possible to reveal the effects of the nature of included cations and specifically adsorbed supporting-electrolyte anions on the adsorption behavior of cryptates under study.

Adsorption of diprotonated cryptand [2.2.2.] on the mercury electrode

“…The series of publications [1][2][3][4][5] was devoted to the electrochemical properties of cryptand [2.2.2.] (CR) and its inclusion complexes with different metal cat ions.…”