Cyclic anodic shift

Fig. 8 Plots of cyclic voltammograms of abcp-substituted triruthenium species 48 and the parent triruthenium complex [Ru30(0Ac)6(py)3]+ in chloromethane solution of (Bu4N)(PFg), showing anodic shifts of redox potentials in 48 relative to those in [Ru30(0Ac)6(py)3] +...

Obtained by both cyclic (100 mV s-1) and square-wave (10 Hz, Osteryoung-type) voltammetry in acetonitrile solution containing 0.1 mol dm-3 BuJNBF4 as supporting electrolyte. Solutions were 1 x 10-3 mol dm-3 in compound with reference to an Ag/Ag+ electrode (330 10 mV vs SCE) at 21 1°G b Anodic shift of the reduction waves of [57] in the presence of 1.0 equiv of the respective cationic species added as their perchlorate or hexafluorophosphate salts. "Anodic shift in the presence of 2.0 equiv of the respective cations. The second reduction wave of [57] became obscure or disappeared in the presence of more than 1 equiv of the respective cations. 

The cyclic voltammetry studies of 9b-d also revealed the presence of four quasi-reversible reduction waves at values similar to those found for the reference compounds (10, 11). Importantly, when comparing the oxidation potentials of 10 and 11 with those of the triads 9b-d and exTTF, the potentials converge with those of pristine exTTF (around 0.33 V). In the triads, the first oxidation is found anodically shifted relative to pristine exTTF. This confirms its strong donating character. On the other hand, with increasing bridge length the exTTF oxidation... 

Cyclic voltammograms of (26) were recorded after addition of calculated equivalents of Na +, K+, and Mg2 + equimolar mixtures of Na+/ K+ and Na + /K + /Mg2 +. The results obtained are presented in Table V. Predictable one-wave metal cation-induced anodic shifts of the ferrocenyl redox couple are observed, and interestingly the magnitudes of these are approximately double those induced by the same metal cations in the redox couple of the mono-substituted vinylic ionophore (15) (See Table III). 

The electrochemical properties of (40)-(47) in the presence and absence of stoichiometric amounts of Na+ and K+ guest cations were investigated in acetonitile solution by cyclic voltammetry. Table VI shows that addition of alkali metal salt in 1 1 molar ratio produces anodic shifts (AE) in the original redox couple of 40-320 mV in the reduction potentials of the respective host s molybdenum redox center. Comparing (45)-(47) with the organic redox-active quinone systems described earlier (see Table I), in the case of Na+ guest cation these AE... 

Ferrocene cryptands have also been studied as cation receptors. Hall ef al. have investigated the coordination of alkaline earth and lanthanide metal cations by cryptand 16 using cyclic voltammetry in CH3GN solution.The cation-induced anodic shift of the Fc/Fc redox couple was found to broadly correlate with the charge density of the cationic guest. Further electrochemical analysis revealed evidence that upon oxidation the 16 Be and 16 Dy complexes readily eject the bound cation from the cryptand cavity, presumably due to electrostatic repulsion. 

Abstract. A series of cyclic polyethers, which incorporate the redox active Mo(NO)P moiety, have been prepared and characterised. The electrochemistry of these complexes has been investigated and their reduction potentials found to undergo anodic shifts upon the binding of alkali metal cations to the cyclic polyether moiety. The magnitude of the shift appears relatively insensitive to the size of the cyclic polyether ring, but is substantially reduced when K " is used in place of Na . 

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