The electrochemistry and the kinetics of the formation of ruthenium(II) nitrogen complexes

1968 ◽  
Vol 46 (16) ◽  
pp. 2743-2747 ◽  
Author(s):  
I. J. Itzkovitch ◽  
John A. Page
Keyword(s):  
Mercury Electrode ◽  
Reduction Wave ◽  
Base Electrolyte ◽  
Mercury Cathode ◽  
Standard Calomel Electrode ◽  
Oxidation Wave ◽  
Dropping Mercury Electrode ◽  
Aqueous Base ◽  
Electron Reduction ◽  
Ar Gas

Electrolysis at a mercury cathode controlled at −0.50 V (vs. standard calomel electrode s.c.e.) in a H2SO4–K2SO4 electrolyte with pH of 2.6 and saturated with Ar gas has been used to prepare RuII–(NH3)5X. The reaction of this species with N2 in the aqueous base electrolyte at 26 °C has been studied and found to follow the equations:[Formula: see text]In base electrolyte saturated with N2 at 1 atm (CN2 ≈ 6 × 10−4 M) the value of the apparent first order constant, k′m is 4.4 × 10−5 s−1 and the value of kd is 4.2 × 10−2 1 mole−1 s−1.The electrochemistry of the various ruthenium species was also investigated in the H2SO4–K2SO4 electrolyte. At the dropping mercury electrode, RuIII (NH3)5Cl gave a well-defined one electron reduction wave with E1/2 = −0.27 V; RuII (NH3)5X gave a well-defined one electron oxidation wave with E1/2 = −0.25 V. The nitrogen complexes gave oxidation waves at a rotating platinum microelectrode, the monomer with E1/2 = +0.72 V and the dimer with E1/2 = +0.78 V.

Electrochemical generation of hydridopentamminerhodium(III) and its reaction with molecular oxygen

1969 ◽  
Vol 47 (22) ◽  
pp. 4241-4246 ◽  
Author(s):  
Leslie E. Johnston ◽  
John A. Page
Keyword(s):  
Molecular Oxygen ◽  
Saturated Calomel Electrode ◽  
Mercury Electrode ◽  
Reduction Wave ◽  
Polarographic Reduction ◽  
Ammoniacal Solution ◽  
Electrochemical Generation ◽  
Dropping Mercury Electrode

The electrochemistry of Rh(NH3)5OH2+ has been studied in a buffered ammoniacal solution. The polarographic reduction wave at the dropping mercury electrode had E1/20 equal to −1.10 V (vs. saturated calomel electrode) in a 0.10 M NH3 – 0.10 M NH4ClO4 electrolyte, and gross Hg cathode electrolysis at −1.19 V produced a stable Rh(NH3)5H2+ hydride species. Both reductions were found to take place through a Rh(I) intermediate.The reaction of the Rh(NH3)5H2+ with molecular O2 in the ammoniacal electrolyte was also studied. The product was demonstrated to be a stable Rh(NH3)4(OH)(O2H)+ hydroperoxo species.

Polarography of 2,2′-Bipyridyl Dimethiodide in Aqueous Solution

1974 ◽  
Vol 29 (1-2) ◽  
pp. 89-90 ◽  
Author(s):  
L. A. Summers
Keyword(s):  
Aqueous Solution ◽  
Radical Cation ◽  
Reduction Wave ◽  
Standard Calomel Electrode ◽  
Ph Dependent ◽  
Electron Reduction ◽  
Ph Range

2,2′-Bipyridyl dimethiodide in aqueous solution in the pH range 5.0-8.9 gives a symmetrical one-electron reduction wave independent of pH and concentration at a potential of —0.96 V against a standard calomel electrode due to the formation of the corresponding radical cation. At a much lower potential it also shows a second reduction wave which is pH dependent.

Polarography of aromatic azo compounds. II. Kinetic study of the disproportionation of 4-Aminohydrazobenzene-4'-sulphonic acid

1965 ◽  
Vol 18 (5) ◽  
pp. 619 ◽  
Author(s):  
TM Florence
Keyword(s):  
Mercury Electrode ◽  
Sulphonic Acid ◽  
Azo Compounds ◽  
Rate Determining Step ◽  
A Value ◽  
Controlled Potential Electrolysis ◽  
Mercury Cathode ◽  
Dropping Mercury Electrode ◽  
Controlled Potential ◽  
Aromatic Azo Compounds

Solutions of 4-aminoazobenzene-4'-sulphonic acid were reduced by controlled potential electrolysis at a mercury cathode, and the disproportionation rate of the hydrazo derivative determined by spectrophotometry and polarography. The kinetics of the reaction were found to be first-order with respect to both hydrazo and hydrogen ion concentrations, although the overall reaction involved two molecules of the hydrazo compound. In the rate law, -d[hydrazo]/dt = k[H+][hydrazo], k was calculated to be (5.0�0.3) x 106 l. mole-1 sec-1 from spectrophotometric measurements, and (4.5�0.5) x 106 l. mole-1 sec-1 by polarography (25�). A reaction mechanism based on a rate determining step involving a quinonediimine intermediate has been proposed. Another value of the disproportionation rate constant was obtained from the effect of drop time on the limiting currents of 4-aminoazobenzene-4'-sulphonic acid at the dropping mercury electrode. A value of k of (22�5) x 106 l. mole-1 sec-1 was determined by this method. Reasons for the discrepancy between this result, and those found by direct measurement, are discussed.

Polarography and coulometry of Rh(III) in a pyridine – pyridinium chloride electrolyte

1969 ◽  
Vol 47 (12) ◽  
pp. 2123-2135 ◽  
Author(s):  
Leslie E. Johnston ◽  
John A. Page
Keyword(s):  
Mercury Electrode ◽  
Normal Wave ◽  
Bulk Solution ◽  
Pyridinium Chloride ◽  
Chloride Electrolyte ◽  
Catalytic Wave ◽  
Controlled Potential Electrolysis ◽  
Dropping Mercury Electrode ◽  
Controlled Potential ◽  
Electron Reduction

The polarography and coulometry of Rh(III) has been studied in an aqueous pyridine–pyridinium chloride–sodium chloride electrolyte at pH 5.30 and ionic strength 0.30 M at 25.0 °C. Two distinct types of polarographic behavior were noted as the total Py concentration was varied between 0.05 and 0.45 M, a "normal" wave with E1/2 of −0.43 V vs. a standard calomel electrode, and a second catalytic wave which under some conditions masked the normal wave.For both types of behavior, controlled potential electrolysis gave a well-defined two electron reduction but there was a definite H+ consumption in the electrolyses. It is postulated that hydride species are involved in the reduction according to the scheme[Formula: see text]surface reaction at dropping mercury electrode[Formula: see text]slow, bulk solution in controlled potential electrolysis

Electrochemical Reduction Behavior Of Mephedrone Drug At A Dropping Mercury Electrode And Its Pharmaceutical Determination In Spiked Human Urine Samples

2012 ◽  
Vol 1 (4) ◽  
pp. 14-17
Author(s):  
V. Krishnaiah V. Krishnaiah ◽  
◽  
Y. V. Rami Reddy ◽  
V. Hanuman Reddy ◽  
M. Thirupalu Reddy ◽  
...  
Keyword(s):  
Electrochemical Reduction ◽  
Human Urine ◽  
Mercury Electrode ◽  
Urine Samples ◽  
Reduction Behavior ◽  
Human Urine Samples ◽  
Dropping Mercury Electrode ◽  
Spiked Human Urine
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