Abstract

Woodward and co-workers in 1952 characterised the unique structural features of ferrocene (the first sandwich compound), demonstrated its aromatic nature and observed that on treatment with mild oxidising agents (aqueous Ag₂SO₄, p-benzoquinone in organic solvents) the orange solution of ferrocene (Fc) turned blue due to the formation of ferrocenium (Fc⁺). A few months later, the one-electron Fc/Fc⁺ redox change was characterised polarographically by Page and Wilkinson with E_1/2 = 0.31 V vs SCE (0.56 V vs NHE) in ethanol/water 9:1. Since then ferrocene has become an icon of organometallic electrochemistry. Owing to the stability of its molecular framework, to the ease of functionalisation at the cyclopentadienyl rings and to the fast, reversible and kinetically uncomplicated Fc/Fc⁺ redox change, ferrocene has been used as a building block for the design of switchable functional systems. In this review, we will consider (1) electrochemical sensors for metal ions, anions and metal–anion pairs operating through the Fc/Fc⁺ redox change, (2) ferrocene-based redox switches of fluorescence and (3) cross-transport of electrons and anions through a liquid membrane mediated by lipophilic ferrocene derivatives.

Graphic abstract

中文翻译：

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二茂铁/二茂铁：多功能氧化还原开关

摘要

伍德沃德和他的同事在1952年对二茂铁（第一个夹心化合物）的独特结构特征进行了表征，证明了其芳香性，并观察到在用弱氧化剂（Ag ₂ SO ₄水溶液，对苯醌在有机溶剂中）处理时，橙色二茂铁（Fc）的溶液由于二茂铁（Fc ⁺）的形成而变成蓝色。几个月后，Page和Wilkinson用E _1/2极谱法表征了单电子Fc / Fc ⁺氧化还原变化 在乙醇/水9：1中，SCE = 0.31 V vs SCE（0.56 V vs NHE）。从那时起，二茂铁已成为有机金属电化学的标志。由于其分子框架的稳定性，在环戊二烯基环处易于官能化以及快速，可逆且动力学上不复杂的Fc / Fc ⁺氧化还原变化，二茂铁已被用作可切换功能系统设计的基础。在本综述中，我们将考虑（1）通过Fc / Fc ⁺氧化还原变化操作的金属离子，阴离子和金属-阴离子对的电化学传感器，（2）基于二茂铁的荧光氧化还原开关，以及（3）交叉转运电子和阴离子通过亲脂性二茂铁衍生物介导的液膜。

图形摘要