Electrochemical properties of n-sulfonatothiacalyx[4]arene complexes with Fe³⁺ and [Co(dipy)₃]³⁺ ions

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• 作者：N. V. Nastapova ; A. S. Stepanov ; V. V. Yanilkin ; V. A. Burilov ; V. V. Skripacheva ; A. R. Mustafina ; S. E. Solov鈥檈va and A. I. Konovalov
• 关键词：n ; sulfonatothiacalyx[4]arene ; [Co(dipy)3]3+ and Fe3+ ions ; complex ; electrochemical reduction
• 刊名：Russian Journal of Electrochemistry
• 出版时间：July, 2009
• 出版年：2009
• 期刊代码：51_10231935
• 类别：mt
• 卷：45
• 期：7
• 页码：783-794
• 数据来源：sp

摘要

The electrochemical properties of n-sulfonatothiacalyx[4]arene (H₄XNa₄) complexes with [Co(dipy)₃]3+ and Fe3+ ions were studied by means of cyclic voltammetry in aqueous solution at pH 2.5. The observed single-electron reduction of [Co(dipy)₃]3+ bound extraspherically to the upper rim and Fe3+ ion bound intraspherically to the lower rim of n-sulfonatothiacalyx[4]arene in binary [Co(dipy)₃]3+ 路 H₃X5−, H₃X5− 路 Fe3+, and ternary [Co(dipy)₃]3+ 路 H₃X5− 路 Fe3+ heterometal complexes was more difficult than in the free state. The reversible single-electron transfer to the metal ion results in lower binding energy ([Co(dipy)₃]3+, ΔΔG ₀ = 3.9 kJ/mol) or in full fast dissociation of the complex (Fe3+). The ternary complex in the solution forms the aggregates, in which inner encapsulated Fe(III) and Co(III) ions are not reduced on the electrode. Their quantitative reduction takes place by the relay mechanism of intra- and intermolecular electron transfer through electrochemically generated [Co(dipy)₃]2+ outer ions.