Viologen derivatives, redox-active

Redox molecules are particularly interesting for an electrochemical approach, because they offer addressable (functional) energy states in an electrochemically accessible potential window, which can be tuned upon polarization between oxidized and reduced states. The difference in the junction conductance of the oxidized and the reduced forms of redox molecules may span several orders of magnitude. Examples of functional molecules used in these studies include porphyrins [31,153], viologens [33, 34,110,114,154,155], aniline and thiophene oligomers [113, 146, 156, 157], metal-organic terpyridine complexes [46, 158-163], carotenes [164], nitro derivatives of OPE (OPV) [165, 166], ferrocene [150, 167, 168], perylene tetracarboxylic bisimide [141, 169, 170], tetrathia-fulvalenes [155], fullerene derivatives [171], redox-active proteins [109, 172-174], and hydroxyquinones [175]. 

Electron-anion antiport has been realized, for instance with redox active carriers such as ferrocene derivatives [6.51a] or alkylviologens [6.44-6.46,6.51b] via ferricinium or reduced viologen species, respectively. The latter have been used extensively in light-driven systems and in studies on solar energy conversion [6.44-6.46],... 

Electrolyte Gating in (Single) Molecule Junctions Containing Redox-Active Viologen Derivatives... 

Evans and coworkers have published an interesting study of the electrochemical behavior of a ferrocene-carboxylic acid derivative in the presence of BCD [18] and a summary of general guidelines on the electrochemical methodology that can be used to assess the complexation of redox-active molecules by cyclodextrin hosts [19]. However, the amphiphilic character of the surfactant viologens used in this work prevented us from applying most of these methods because the voltammetric... 

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