A High-Sensitive Polarography in Highly Viscous Supporting Electrolyte Solution Using Stationary Mercury Electrode

The oxidative behavior of Auranofin, 2,3,4,6-tetra-O-acetyl-1-thio-β -D-glucopyranosato- S(triethylphosphine)gold(I), was investigated by using cyclic voltammetry (CV) in 0.1 M Bu4NPF6/CH2Cl2 and 0.1 M Bu4NPF4/CH2Cl2 solutions using Pt working and auxiliary electrodes and a Ag/AgCI reference. CV studies at scan rates from 50-2,000 mV/s and Auranofin concentrations between 1 and 4 mM, show two irreversible oxidation processes occurring at +1.1 V and +1.6 V vs. Ag/AgCl. Ph3PAu (p-thiocresolate) was also investigated as a reference for comparison of the oxidation processes in Auranofin to that of other phosphine gold thiolate complexes previously reported. The electrochemical response appears to be sensitive to adsorption at the electrode as well as to the nature of the supporting electrolyte solution. Repeated cycling shows a build up of products at the electrode.

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The reaction between monosilicic acid and aluminium hydroxide. I. Kinetics of adsorption of silicic acid by aluminium hydroxide

Soil Research ◽

10.1071/sr9670295 ◽

1967 ◽

Vol 5 (2) ◽

pp. 295 ◽

Cited By ~ 60

Author(s):

FJ Hingston ◽

M Raupach

Keyword(s):

Ionic Strength ◽

Silicic Acid ◽

Electrolyte Solution ◽

Aluminium Hydroxide ◽

Solid Phase ◽

Supporting Electrolyte ◽

Kcal Mole ◽

Monosilicic Acid ◽

Kinetics Of ◽

Supporting Electrolyte Solution

Studies of the reaction between monosilicic acid and crystalline aluminium hydroxide showed that a number of layers of silicic acid could be formed on the surface of the hydroxide. Silicate is considered to be adsorbed as silicic acid rather than as silicate ions. The first layer was produced by rapid reaction of silicic acid with the surface of aluminium hydroxide. The isotherm for this initial reaction was not affected by varying the temperature from 10 to 35�C or by increasing the ionic strength of the supporting electrolyte solution. Adsorption of silicic acid resulted in increased KOH uptake by (or H2SO4 displacement from) the solid phase, which corresponded to a decrease in pH of the suspension. Subsequent layer formation was slower; the rate increased both with increasing temperature and with the ionic strength of the supporting electrolyte solution. Study of the kinetics of the reaction showed that these layers could have formed by polymerization of silicic acid on the hydroxide surface. The activation energy for the reaction increased with increasing surface coverage from 15 to 24 kcal/mole for the second layer and was about 24 kcal/mole for the third layer.

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Studies of a Mixed Adsorption Layer of Butan-1-ol and o-Toluidine on Mercury Electrode

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20021579 ◽

2002 ◽

Vol 67 (11) ◽

pp. 1579-1588 ◽

Cited By ~ 1

Author(s):

Dorota Sieńko ◽

Dorota Gugała ◽

Jolanta Nieszporek ◽

Joanna Jankowska ◽

Jadwiga Saba

Keyword(s):

Thermodynamic Analysis ◽

Adsorption Layer ◽

Supporting Electrolyte ◽

Mercury Electrode ◽

Interaction Constant ◽

Repulsive Interaction ◽

Surface Excess ◽

Adsorption Parameters ◽

Frumkin Isotherm ◽

Adsorption Layers

The results of thermodynamic analysis of o-toluidine adsorption on a mercury electrode in the presence of various butan-1-ol amounts complete our previous studies on properties of mixed adsorption layers of toluidine isomers-butan-1-ol. The values of the relative surface excess Γ'°T obtained for o-toluidine show that adsorption of this compound decreases with increasing of butan-1-ol concentration. Analysis of adsorption parameters derived from the Frumkin isotherm indicates that in the presence of 0.33 M BuOH in 1 M NaClO4 with adjusted pH 3 as supporting electrolyte, ∆G0 values for o-toluidine are the highest and, at the same time, the strongest repulsive interaction occurs. In the presence of 0.11 M butan-1-ol, smaller values of ∆G0 for o-toluidine correspond to weaker repulsive interaction. Therefore the change of the Γ'°T value for o-toluidine as a function of butan-1-ol concentration is the result of mutual changes of ∆G0 and interaction constant A between adsorbate molecules.

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Polarography of nickel in concentrated chloride media

Australian Journal of Chemistry ◽

10.1071/ch9661343 ◽

1966 ◽

Vol 19 (8) ◽

pp. 1343 ◽

Cited By ~ 17

Author(s):

TM Florence

Keyword(s):

Ionic Strength ◽

Graphite Electrode ◽

Supporting Electrolyte ◽

Anhydrous Methanol ◽

Pyrolytic Graphite ◽

Hydration Number ◽

Mercury Electrode ◽

Specific Adsorption ◽

Dropping Mercury Electrode ◽

Pyrolytic Graphite Electrode

In concentrated chloride media, nickel is reduced at far more positive potentials than in dilute solutions. The positive shift in half-wave potential increases as the ionic strength is raised, and is also greater when the cation of the supporting electrolyte has a high hydration number. Evidence is presented to show that the reduction in overpotential is due to the formation of a nickel chloride complex, [Ni(H2O)5Cl]+, which has a stoicheiometric stability constant of 0.094 � 0.009 at an ionic strength of 10.0. Spectrophotometric results show that this nickel species is not formed in low ionic strength solutions. In anhydrous methanol saturated with lithium chloride, nickel is present as the tetrachloro complex, [NiCl,]2-, which has similar polarographic behaviour to the monochloro complex. Current-potential curves recorded at a rotated pyrolytic graphite electrode enabled the behaviour of nickel to be studied in the absence of specific adsorption of the chloride ion. Nickel is reduced at more positive potentials at a dropping mercury electrode than at the pyrolytic graphite electrode, and the results indicate that this difference is due to specific adsorption of chloride on the mercury electrode.

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