Redox homogeneous self-exchange

Given the importance and great variety of electron-transfer reactions of polypyridine complexes, systematic kinetic studies are surprisingly scarce and only few kinetic data are available. Some representative rate constant values for homogeneous self-exchange redox reactions were reported ... 

Fig. 8.3. Log-log plot for estimated electron-transfer rate constant (ifi) vs. homogeneous self-exchange rate constants (lexc) for redox systems Fe2+/3+ (lxlO-3 M-i s 0, Ru(NH3)e2+ 3+ (4xlQ3 M l s O, Fe(CN)63 - (2xl0< M-i sO and IrCle (2xlOS Mi sO. (o) (ill), ( ) (100) and (x) polycrystaUine BDD electrodes. The soM line was calculated from the simple Marcus relation (ref. 6)...

Three processes can control the rate of homogeneous charge transport through a redox-active polymer film, i.e. electron self-exchange between redox-active centers,... 

The double-layer effects are significantly reduced when one of the partners in the redox couple is uncharged. This is the case of ferrocene, which was treated in detail for gas phase and homogenous solution self-exchanges. The standard rate constants for the electro-oxidation of ferrocene at a platinum electrode in acetonitrile range from 0.02 to 220 cm sec" [46]. Some of the observed scatter is related to differences in electrolyte nature and concentration, or in temperature, but also reflects the experimental errors of some of the techniques employed. Fawcett and OpaUo reviewed these data and recommended a... 

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