Supramolekulare Elektrochemie

Abstract

Welche Möglichkeiten bietet die Elektrochemie der supramolekularen Chemie? Einerseits liefert sie Informationen, die mit spektroskopischen und massenspektrometrischen Methoden nicht zugänglich sind, andererseits lassen sich mit ihr supramolekulare Wechselwirkungen beeinflussen. Rechts ist exemplarisch das Cyclovoltammogramm des gezeigten Lanthan‐Kryptats abgebildet; nur die ersten drei Reduktionen werden registriert, obwohl insgesamt sechs Elektronen auf die Bipyridineinheiten übertragen werden können (E in V gegen Ferrocen/Ferrocenium).

Molecular Electrochemistry of Cyclophanes

“…Aza [3]ferrocenophanes such as 21 [73][74][75] are easily oxidized at potentials close to the ferrocene oxidation itself. However, as a complication, (de)protonation reactions at the N atom play a role.…”

“…Although various general accounts of cyclophane chemistry are available, only a few (see e.g. [3,4]) mention electrochemical redox reactions of such compounds in a systematic manner.…”

“…Further interesting effects were observed in the case of hetera [3]ferrocenophanes with S and Se as hetero atoms (20, X = S, Se, or CH 2 ). Values of E 0 for various derivatives were compared to those for 1,1'-bis(methylthio)-and 1,1'-bis(methylseleno)ferrocene [72].…”

“…Inversely, the effect of protonation at the N site on the fc redox potential is explained by a Coulombic model, and the maximum shift of E 0 has been estimated as 390 mV (for a detailed discussion of the sensing application of such fc derivatives, see ref. [3]). …”

“…It was already observed early [86] that the solvent had a marked effect on the shape of the voltammograms: while in CH 3 CN several examples of fully overlapping two-electron waves were observed, in CH 2 Cl 2 two separate one-electron signals occur. The CV for the reduction of 30 in propylene carbonate just shows the beginning of this splitting by a distortion of the CV curve shape, and becomes clearly visible in CH 2 Cl 2 (Fig.…”