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用pH电位法测定了硫代脯氨酸的质子化常数和Ni(Ⅱ)、Co(Ⅱ)、Zn(Ⅱ)-硫代脯氨酸络合物的稳定常数.用量热法测量了硫代脯氨酸的离解热以及它与上述金属离子络合反应的焓变,进而计算了各络合反应的吉氏自由能、熵变等热力学参数.结果表明在25±0.2℃、I=0.15(NaClO_4)条件下,硫代脯氨酸金属络合物的吉氏自由能递变顺序为Ni(Ⅱ)>Co(Ⅱ)≈Zn(Ⅱ).基本上符合Irving-Williams序列,而且络合物稳定性可能主要取决于焓变大小.这些实验数据可为深入研究硫代脯氨酸金属络合物在体液中的性质和行为提供有用信息.
The protonation constants of thioproline and the stability constants of Ni (Ⅱ), Co (Ⅱ) and Zn (Ⅱ) -thioproline complexes were measured by pH potentiometry.The thio Proline dissociation heat and its enthalpy change with the above metal ion complexation reaction, and then calculate the thermodynamic parameters such as Gibbs free energy and entropy change of each complexation reaction. The results show that at 25 ± 0.2 ℃, I = 0.15 ( NaClO_4), the order of the Gibbs free energy for the metalloxylithion prolongs is Ni (Ⅱ)> Co (Ⅱ) ≈Zn (Ⅱ). It basically conforms to the Irving-Williams sequence, and the complex The stability may depend primarily on the enthalpy change.These experimental data provide useful information for further investigation of the properties and behavior of thiopropionate metal complexes in body fluids.