NMR Study of the Stoichiometry, Stability, and Ligand Interchange of Silver Ion-Hexathia-18-crown-6 Complex in Binary Dimethyl Sulfoxide Solvent Mixtures at 300 K |
| |
Authors: | Mojtaba Shamsipur Zahra Talebpour Naader Alizadeh |
| |
Institution: | (1) Department of Chemistry, Razi University, Kermanshah, Iran;(2) Department of Chemistry, Tarbiat Modarres University, Tehran, Iran |
| |
Abstract: | Proton NMR was used to study the complexation reaction between silver ion and hexathia-18-crown-6 in a number of binary mixed solvents of dimethyl sulfoxide with acetonitrile and methanol. Formation constants for the resulting 1:1 complexes in different solvent mixtures were determined by computer fitting of the chemical shift-mole ratio data. The influence of solvent composition on the stability of the resulting complex is discussed. The exchange kinetics of Ag+-hexathia-18-crown-6 in 70-30 wt.% dimethyl sulfoxide-acetonitrile and 75-25 wt.% dimethyl sulfoxide-methanol were studied by proton NMR line-shape analysis. In both solvent mixtures, the exchange of thiacrown ether between the free and complexed sites was found to proceed via a dissociative pathway. The exchange rates and the activation parameters E
a, H
, S, and G for the ligand exchange were determined and the influence of solvent properties on these parameters discussed. |
| |
Keywords: | Hexathia-18-crown-6 silver ion mixed solvent complex stability exchange kinetics proton NMR dimethyl sulfoxide acetone methanol |
本文献已被 SpringerLink 等数据库收录! |
|