Reversible Charge Transfer Research Articles

Tribenzylborane. A Charge-transfer model for benzyl-group Va metalloid electronic transitions and phenonium ion transition states

Abstract : The ultraviolet spectra of aryl derivatives of trivalent group V elements (M) such as C6H5M(CH3)2 exhibit intense transitions in the region 240-300 nm and there has been substantial difference of opinion as to whether these transitions should be regarded as 1L(a), 1L(b), n pi* or intramolecular charge transfer. Reported is the observation of a similar but reverse charge transfer transition in the spectra or para substituted tribenzylboranes (p-RC6H4CH2) 3B where R is H,F,CH3O, and CH3. The authors feel that these results firmly establish these transitions in the spectra of (C6H5CH2) 3B and the corresponding transition 300 nm in the spectra of triarylboranes as intramolecular charge transfer. (Author)

Charge Transfer Processes at Organic Insulator Electrodes

Charge transfer reactions at insulator electrodes are discussed in terms of the model developed for such processes at semiconductor electrodes. A simplifying condition here is that only such reactions are possible which lead to the injection of holes into the valence band or of electrons into the conduction band. Measurements at anthracene electrodes showed complete agreement with the predictions derived from the model including the possibility of having reversible charge transfer reactions.

Electroanalytical study of the cobalt(II) pyridine—cobalt amalgam system, with application to stripping analysis

The electroreduction of cobalt (II) from solutions containing pyridine was investigated with stationary electrode polarography at a hanging mercury drop electrode using both single-scan and cyclic experiments. Scan rates ranged from 50 mV sec to 110 V sec , and from the variation of the peak potential and the peak current function, i p/ V v, (where i p is the peak current, and v the rate of voltage scan) with scan rate, the reduction appeared to involve a reversible charge transfer followed by an extremely rapid chemical reaction in the amalgam to form a species not electroactive in the same potential range. This product appears to be a dimer or higher cobalt aggregate dissolved in the mercury. It is reoxidized at a potential about 1 V anodic of the reduction wave. This irreversible anodic wave was made the basis of a stripping analysis procedure for the determination of trace quantities of cobalt.

Alternating current polarography with multi-step charge transfer: I. Theory for systems with reversible two-step charge transfer

A theory is given for the a.c. polarographic wave with two-step charge transfer in which the overall electrode process is controlled kinetically solely by diffusion (the “reversible” or “Nernstian” case). Topics discussed are: (a) a method of derivation applicable to fundamental and higher harmonic alternating currents ; (b) predictions of equations; (c) conditions under which diffusion-controlled two-step and single-step mechanisms are distinguishable; (d) the relative sensitivity of d.c. and a.c. methods to differences between single-step and two-step mechanisms; (e) methods of calculating standard potentials from a.c. polarographic data.