Abstract

The stability constants of cobalt(II) glycylglycinate complexes in water–ethanol solvent of variable composition are determined potentiometrically at 298 K and an ionic strength of the solutions (NaClO₄) of 0.1. The stability of cobalt(II) complexes with glycylglycinate ion is found to increase with ethanol content in the solution. The resulting stability constants of cobalt(II) glycylglycinate are compared to the literature data on the stabilities of nickel(II) and copper(II) complexes with glycylglycine ion. The contributions of resolvation of the reagents to changes in the Gibbs free energy of cobalt(II) glycylglycinate formation in water–ethanol solvent are evaluated. The increase in stability of the complexes with glycylglycinate ion is mainly caused by weakening of ligand solvation as one proceeds from water to water–ethanol solvents.

中文翻译：

---

EtOH：H 2 O溶液的组成对甘氨酸甘氨酸钴（II）配合物稳定性的影响

摘要

可变组成的水-乙醇溶剂中的甘氨酸钴（II）配合物的稳定常数是在298 K电位和溶液的离子强度（NaClO ₄）的0.1。发现钴（II）与甘氨酸甘氨酸盐离子的配合物的稳定性随溶液中乙醇含量的增加而增加。将得到的甘氨酸钴（II）的稳定常数与关于镍（II）和铜（II）与甘氨酰甘氨酸离子配合物的稳定性的文献数据进行比较。评估了试剂的溶解对水-乙醇溶剂中钴（II）甘氨酸钴（II）形成的吉布斯自由能变化的贡献。与甘氨酸甘氨酸酯离子配合物的稳定性提高主要是由于配体溶剂化作用从水向水-乙醇溶剂的转化过程减弱所致。