Oxygen Reduction Catalyzed by a Fluorinated Tetraphenylporphyrin Free Base at Liquid/Liquid Interfaces

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• 作者：Imren Hatay ; Bin Su ; Manuel A. Mndez ; Clmence Corminboeuf ; Tony Khoury ; Claude P. Gros ; Mlanie Bourdillon ; Michel Meyer ; Jean-Michel Barbe ; Mustafa Ersoz ; Stanislav Z&#225 ; li ; Zdenk Samec ; Hubert H. Gi
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：October 6, 2010
• 年：2010
• 卷：132
• 期：39
• 页码：13733-13741
• 全文大小：409K
• 年卷期：v.132,no.39(October 6, 2010)
• ISSN：1520-5126

文摘

The diprotonated form of a fluorinated free base porphyrin, namely 5-(p-aminophenyl)-10,15,20-tris(pentafluorophenyl)porphyrin (H₂FAP), can catalyze the reduction of oxygen by a weak electron donor, namely ferrocene (Fc). At a water/1,2-dichloroethane interface, the interfacial formation of H₄FAP²⁺ is observed by UV−vis spectroscopy and ion-transfer voltammetry, due to the double protonation of H₂FAP at the imino nitrogen atoms in the tetrapyrrole ring. H₄FAP²⁺ is shown to bind oxygen, and the complex in the organic phase can easily be reduced by Fc to produce hydrogen peroxide as studied by two-phase reactions with the Galvani potential difference between the two phases being controlled by the partition of a common ion. Spectrophotometric measurements performed in 1,2-dichloroethane solutions clearly evidence that reduction of oxygen by Fc catalyzed by H₄FAP²⁺ only occurs in the presence of the tetrakis(pentafluorophenyl)borate (TB⁻) counteranion in the organic phase. Finally, ab initio computations support the catalytic activation of H₄FAP²⁺ on oxygen.