高等学校化学学报

高等学校化学学报 ›› 1993, Vol. 14 ›› Issue (1): 71.

• 研究论文 • 上一篇    下一篇

介质对配合物稳定性的影响(Ⅴ)——Fe(tiron)--NaClO4-C2H5OH-H2O体系

刘魁道, 陈维东, 刘祁涛   

  1. 辽宁大学化学系, 沈阳 110036
  • 收稿日期:1991-12-14 出版日期:1993-01-24 发布日期:1993-01-24
  • 通讯作者: 刘祁涛
  • 基金资助:

    国家自然科学基金

The Influence of Medium on the Stability of Coordination Compounds (Ⅴ)——The System of Fe(tiron)-NaClO4-C2H5OH-H2O System

LIU Kui-Dao, CHEN Wei-Dong, LIU Qi-Tao   

  1. Department of Chemistry, Liaoing University, Shenyang, 110036
  • Received:1991-12-14 Online:1993-01-24 Published:1993-01-24

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摘要： 用分光光度法于295±1K温度下测定了由高价阳离子Fe3+和高价阴离子tiron4-(3,5-二磺酸基邻苯二酚)形成的配阴离子Fe(tiron)-在乙醇-水混合溶剂中的稳定常数随离子强度的变化。分别用推广的Debye-Hückel方程和Pitzer方程计算了配阴离子的热力学稳定常数,发现对本体系De-bye-Hückel方程完全不能适用,而基于Pitzer方程的多项式逼近法则可得到满意的结果。讨论了介质效应和配合反应的标准迁移自由能。

关键词: Fe(tiron)-, 配合物的稳定性, Pitzer方程, 介质效应

Abstract: The stability of complex anion Fe(tiron)- composing of high valence cation Fe3+ and anion tiron4- in mixed solvents of ethanol-water with weight percentage of ethanol 0, 5, 15, 25, 35 and 50 was measured spectrophotometrically at 295 Kby using NaClO4 as the supporting electrolyte with ionic strength ranging from 0.1-3.9 mol/L.The thermodynamic stability constants of Fe(tiron) in various mixed solvents have been obtained by a polynomial approximation equation based on Pitzer's theory.As a comparison, the traditional Debye-Huckel equation was used to treat the same data.The results show that this polynomial approximate method is obviously superior to the previous one.It was discovered that there is a linear relation between the thermodynamic stability constants of Fe(tiron)-and the mole fraction of organic component in Mixed solvents or the reciprocal of dielectric constants of the solvents.The medium effect and the standard free energy of transfer AGtr0 for the coordination reaction:Fe3+ 4-tiron4- =Fe(tiron)- is also discussed.

Key words: Fe(tiron), Stability of complexes, Pitzer's equation, Medium effect

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