Potassium cyclic voltammetry

Electrolysis cyclic voltammetry molten salts carbamide potassium chloride ammonium chloride compound adsorbtion. 

In the literature the term soluble Prussian blue introduced by Keggin and Miles [5] to determine the KFeFe(CN)6 compound is still widely used. However, it is important to note, that the term soluble refers to the ease with which the potassium ion can be peptized rather than to the real solubility of Prussian blue. Indeed, it can be easily shown by means of cyclic voltammetry that the stability of Prussian blue films on electrode supports is nearly independent of their saturation by potassium cations. Moreover, Itaya and coworkers [9] have not found any appreciable amount of potassium ions in Prussian blue, which makes doubtful structures like KFeFe(CN)6. Thus, the above equation fully describes the Prussian blue/Prussian white redox reaction. 

Phenols show a two-electron oxidation wave on cyclic voltammetry in acetonitrile at a less positive potential than for the con-esponding methyl ether (Table 6.5) or a related hydrocarbon. Phenol radical-cation is a strong acid with pKg ca. -5 in water [93], so the two-electron oxidation wave for phenols is due to formation of a phenoxonium ion such as 13, where the complete oxidation process is illustrated for 2,4,6-tri-tt rf-butylphenol. Phenoxide ions are oxidised at considerably less positive potentials than the conesponding phenol. They give rise to a one-electron wave on cyclic voltammetry in aqueous acetonitrile or in aqueous ethanol containing potassium hydroxide. 2,4,6-Tri-/ert-butyiphenoxide ion is reversibly oxidised to the radical in a one-electron proces.s with E° = -0.09 V V5. see. The radical undergoes a further irreversible one-electron oxidation with Ep = 1.05 V vs. see on cyclic voltammetry forming the phenoxonium ion which reacts with water [94J. 

The radical anion from 2,3-diphenylquinoxaline has been isolated in the dark blue sodium or potassium salts, 77 and 78, respectively.131 The crystal structures show that the metal is coordinated (Fig. 50) to DME, to the nitrogen atoms of the heterocycle where the negative charge is concentrated, and to ortho and ipso carbon atoms of the adjacent phenyl rings (Na-C 302.2(6)-307.6(6) pm and K-C 312.1(3)-333.3(3) pm). The M-Ph interactions link the ion pairs into infinite chains. The formation and stability of the radical anion have been studied by ESR spectroscopy and cyclic voltammetry. 

A number of ferrocene cryptand molecules (66-74) ((29)—(31)) have been reported in the literature and it is only relatively recently that their electrochemical coordination properties have been disclosed. We have synthesized potassium-selective metallocene cryptands (72) (30) and (31) the electrochemistry of the former in the presence of K+ guest cations proved disappointingly irreversible (75). Hall and co-workers (76) have used cyclic voltammetry to investigate the coordination of... 

Cyclic voltammetry of these compounds shows that the first electron reduction (redox couple) is reversible in aprotic electrolyte solutions. A one-electron reduction of these compounds (except TKDE) results in the corresponding radical-anion form (14). Under aprotic and 02-free conditions the anion forms are sufficiently stable for use as reducing agents for the reduction of polyimide films. Reducing agents also can be generated chemically, as for example, reacting benzoin and potassium l-butoxide under alkaline conditions leads to the benzil radical-anion. 

Rashid and Kalvoda examined this reaction using cyclic voltammetry by measuring the current enhancement for the electro-oxidation of potassium ferricyanide on addition of the amine. Using working curves derived by Nicholson and Shain (1964) relating the ratio of the peak current measured in the presence and absence (i.e. the diffusion-controlled peak current for oxidation of ferricyanide) of the amine to the parameter kfRTInFvioT an EC mechanism, the kinetic parameter, kf, could be calculated. 

The complex [Co3(/A3-CPh)2Cp3] (76) (E = E = CPh) is reduced by potassium metal to a radical anion whose ESR spectrum suggests a symmetrical structure with a half-filled orbital constructed from cobalt 3d atomic orbitals. The cation [76]" (E = E = CPh), detected by cyclic voltammetry ( = 0.34 V) and prepared by electrolytic oxidation, has the unpaired electron in a degenerate orbital, and a structural Jahn-Teller distortion is again expected 189). 

The redox reactions for supported BLMs containing vinylferrocene as an electron mediator have been investigated using cyclic voltammetry. The results have shown the following, (i) Ferrocene can be very easily immobilized in the lipid bilayer on the surface of a metallic wire (s-BLM) system. This demonstrates that the s-BLM system offers a novel approach to electrode modification by simple immobilization of compounds within BLM. (ii) Ferrocene in a BLM increases the sensitivity to the potassium ferri/ferrocyanide ion by about two orders of magnitude in comparison to that of the platinum electrode [79]. 

Reduction of the diborylated naphthalene derivative (52) was studied by Gabbai, who found a reversible reduction wave at —1.81 V (vs. SCE) by cyclic voltammetry. Moreover, treatment of (52) with potassium in THF in the presence of 18-crown-6 led to formation of a dark purple EPR-active solution, the spectrum of which suggested coupling of the electron spin of the free radical with two boron centers (equation 39). The presence of an intramolecular one-electron a-bond in (153) leads to a significant shortening of the boron-boron distance as suggested by DFT calculations. ... 

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