Dynamics of Successive Complex Formation in facilitated

本文提出了一种测定1：1和1：2络合物在液-液界面上促进离子转移的稳定常数的新方法。用电化学法测定了碱金属和碱土金属离子与几种开环和环状聚醚的络合物的稳定常数。并对配体在液-液界面上的吸附效应进行了定量估算。本研究表明，即使在通过与疏水离子载体的快速络合促进的可逆离子转移中，离子-离子载体络合物的载流物种也可能随离子转移电流通过过程中界面附近相关化学物种的浓度分布的动态变化而变化。这种离子-离子载体络合动力学对于确定溶剂萃取中离子的最佳萃取条件以及离子选择电极选择性检测离子具有重要意义。提出了一种将本方法推广到离子准可逆转移络合反应和慢化学反应络合反应的研究方法。

A new method has been proposed for determining the stability constants of 1:1 and 1:2 complexes in facilitated ion transfer across the liquid-liquid interface. The stability constants were determined electrochemically for complexes of alkali and alkaline-earth metal ions with several acyclic and cyclic polyethers. Effect of ligand adsorption at the liquid-liquid interface was also estimated quantitatively. The present study has revealed that even in reversible ion transfer facilitated by fast complexation with hydrophobic ionophores the current carrying species of ion-ionophore complexes may varies depending on the dynamics of concentration profiles of pertinent chemical species in the vicinity of the interface during the passage of ion transfer current. This dynamics of ion-ionophore complexation is important in determining optimal condition of the extraction of ions in solvent extraction and also the selective detection of ions with ion-selective electrode. A way of extending the present method to the study of complex formation involved with quasi-reversible transfer of ions and also complexation with slow chemical reactions is suggested.