Cyclic voltammetry multiple electrons

The electrochemical behavior of heterometallic clusters has been reviewed clsewbcre."" The interest in examining clusters stems from their potential to act as "electron sinks " in principle, an aggregate of several metal atoms may be capable of multiple redox state changes. The incorporation of heterometals provides the opportunity to tune the electrochemical response, effects which should be maximized in very mixed"-metal clusters. Few very mixed -metal clusters have been subjected to detailed electrochemical studies the majority of reports deal with cyclic voltammetry only. Table XII contains a summary of electrochemical investigations of "very mixed"-metal clusters. 

The purity of the terminal Au-oxo complexes, 3 and 4, was established by several methods including P NMR (3 and 4 have only one phosphorus peak at —8.55 and —13.15 ppm, respectively), cyclic voltammetry, electronic absorption spectroscopy, vibrational spectroscopy, detailed magnetic measurements and elemental analysis on all elements (triplicate analyses for Au) (44). The single peak in the PNMR spectra is consistent with the C2V symmetry of 3 and 4 established by multiple X-ray crystallographic structure determinations and a neutron diffraction study on 3 at liquid He... 

The reach of cyclic voltammetry is vast. It has been applied to the investigation of simple electron-transfer reactions those with two successive electron transfers (so-called EE reactions) and with multiple electron transfers (EEE) involving electron transfer to and from compounds, say, with several benzene rings. The technique has been applied to complex sequences in which an electron transfer is followed by a chemical reaction step, and then by another electron transfer (ECE reactions), etc. The complexity of some of the reaction sequences investigated by cyclic voltammetry lends itself well to calculations that need computers the classic work of Feldburg in this direction (digital simulation) has been already mentioned (Section 7.5.19.2). 

Corresponding anodic and cathodic peaks — Corresponding anodic and cathodic peaks are those anodic and cathodic current peaks produced by -> cyclic voltammetry or -> AC voltammetry which are associated with a single electron transfer or with concerted multiple electron transfers (see - concerted electron transfer). 

The oxidation potentials of various fluoroalkyi sulfides, selenides, and tellurides have been determined by use of cyclic voltammetry. These substances exhibit irreversible multiple anodic waves. In Table 5 is summarized the first oxidation peak potentials ( p) of these substances together with those of some nonfluorinated and other electronegatively substituted chalcogeno compounds. In all cases, the fluorinated compounds are oxidized at more positive potentials than the corresponding nonfluorinated compounds because of the electron-withdrawing effects of fluoroalkyi groups. It should be noted... 

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