Electrochemical studies of Schiff base compounds derived from antipyrine nucleus in ethanolic buffer solutions

2000 ◽  
Vol 78 (9) ◽  
pp. 1170-1177 ◽  
Author(s):  
Ibrahim S El-Hallag ◽  
Gad B El-Hefnawy ◽  
Youssef I Moharram ◽  
Enass M Ghoneim
Keyword(s):  
Schiff Base ◽  
Electrochemical Behaviour ◽  
Electrochemical Techniques ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Limiting Current ◽  
Electron Transfer Process ◽  
Buffer Solutions ◽  
Mechanistic Pathway ◽  
Electrochemical Parameters

The electrochemical behaviour of Schiff base compounds derived from an antipyrine nucleus was investigated in 30% (v/v) ethanolic buffer solutions (pH 3-11) using various electrochemical techniques at mercury electrode. The results showed that, the total limiting current of each of the studied compounds corresponds to 2-electron transfer process. The mechanistic pathway of the electrode reaction of the investigated compounds at mercury electrode, the effect of the medium, and the evaluation of the electrode reaction parameters were illustrated and discussed.Key words: Schiff base, antipyrine nucleus, electrode reaction, electrochemical parameters, cyclic voltammetry.

Behaviour of disubstituted dithiocarbamates at the mercury electrode

1975 ◽  
Vol 28 (1) ◽  
pp. 21 ◽  
Author(s):  
TH Randle ◽  
TJ Cardwell ◽  
RJ Magee
Keyword(s):  
Surface Film ◽  
Electrochemical Behaviour ◽  
Mercury Electrode ◽  
Alkyl Substituent ◽  
Electrode Reaction ◽  
Anodic Wave ◽  
Alkyl Groups ◽  
Product Film ◽  
Triton X ◽  
General Method

The electrochemical behaviour at the mercury electrode of a series of sodium dithiocarbamates in aqueous solution has been investigated. Although the overall electrode reaction mechanism is the same as that for sodium diethyldithiocarbamate in each case, the current flowing in the main anodic wave is determined by the nature of the film of the particular insoluble mercury(II) dithiocarbamate deposited on the electrode and varies with the alkyl substituent group in the dithiocarbamate. A porous, loosely bound film which periodically bursts, causing localized stirring and large irregular currents, was indicated for large bulky alkyl groups (e.g. butyl) while for small or planar alkyl groups (e.g. methyl, tetramethylene) current inhibition was observed, suggesting a compact surface film. The influence of the surfactant Triton X-100 on the product film has also been examined. Linear sweep chronoamperometry is recommended as a general method of analysis for dithiocarbamates as the electrolysis time (and therefore the film thickness) can be selected to avoid the above interferences.

scholarly journals Electrochemical and Spectrastudies of Some Sulfa Drug Azodyes and Their Metal Complexes in Aqueous Solution

2017 ◽  
Vol 14 (1) ◽  
pp. 6021-6032 ◽  
Author(s):  
E.M. Mabrouk ◽  
Kh.A.Al Omary ◽  
A.S.Al- Omary ◽  
E.H. El-Mossalamy
Keyword(s):  
Dissociation Constants ◽  
Mercury Electrode ◽  
Reduction Process ◽  
Electrode Reaction ◽  
Formation Constants ◽  
Azo Compounds ◽  
Alkaline Solutions ◽  
Sulfa Drugs ◽  
Sulfa Drug ◽  
Buffer Solutions

The electrochemical behavior of some azo compounds derived from sulfa drugs derivatives in B.R. buffer solutions of different pH containing 20 (v/v) ethanol was investigated at the mercury  electrode using different techniques (DC,DPP,CV and Coulometry) to investigate the effect of medium on the electro reduction process and suggestion the electrode reaction mechanism. The obtained results denoted that these compounds were reduced undergo a single irreversible 4- electron polarographic wave in acid and neutral solutions which represent the cleavage of the N=N center to the amine stage, whereas in alkaline solution, two wave are obtained the second is 2-electron irreversible wave corresponding to the reduction ofCHO group to CH2OH. The DPP and CV data showed a single peak in solutions of pH< 8, whereas three peaks are in alkaline solutions. The dissociation constants of the investigated compounds were determined by using spectrophotometric and potentiometric methods. Also the metal – ligand formation constants were determined potentiometrically and found in the order Cu˃ Co˃ Ni ˃Zn.

Electrochemical reduction of nickel(II) dithiocarboxylates at the mercury electrode

1997 ◽  
Vol 75 (7) ◽  
pp. 1023-1029 ◽  
Author(s):  
A. Safavi ◽  
L. Fotouhi
Keyword(s):  
Electron Transfer ◽  
Electrochemical Techniques ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Ece Mechanism ◽  
Reduction Mechanisms ◽  
Ec Mechanism ◽  
Controlled Potential ◽  
Electron Reduction ◽  
Derivatives Of

The reduction mechanisms of a series of nickel(II) dithiocarboxylate complexes have been investigated in dimethyl sulphoxide at the mercury electrode. Various electrochemical techniques, including polarography, cyclic voltammetry, chronoamperometry, and controlled potential coulometry, were employed. The reduction of the complexes of the acid derivatives of 2-aminocyclopentene-1-dithiocarboxylate (ACD) proceeds initially by an ECE mechanism (electron transfer – chemical reaction – electron transfer) followed by a one-electron irreversible process. The nature of the complete electrode reaction suggests a metal-centered reduction. The nickel complexes of the ester derivatives of ACD underwent a one-electron reduction that was subject to a follow-up catalytic reaction (EC′ mechanism) and the original complex is regenerated through this regeneration reaction. Keywords: reduction, nickel(II) dithiocarboxylate, mercury electrode.

Investigation of The Electrode Pathway of Quinoline Azo Dye Compound via Convolutive Voltammetry and Digital Simulation

2016 ◽  
Vol 19 (2) ◽  
pp. 091-095 ◽  
Author(s):  
A. Al-Owais ◽  
I. S. El-Hallag
Keyword(s):  
Cyclic Voltammetry ◽  
Azo Dye ◽  
Digital Simulation ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Alkaline Solutions ◽  
Reduction Wave ◽  
Electron Wave ◽  
Electrochemical Parameters ◽  
Ph Dependent

The electrochemical behavior and the electrode reaction of quinolone azo dye compound was investigated using convolutive cyclic voltammetry at mercury electrode in 50% (v/v) ethanolic Britton-Robinson solutions of pH 2.5 – 12.0. Four electrons slow reduction wave was consumed in acidic and alkaline solutions corresponding to the reduction of the more easily N = N center. A second more cathodic irreversible , pH – dependent, 2-electron wave represents the reduction of quinolone ring. Cyclic voltammetry and convolution transforms were used to determine the kinetic parameters of the electroactive species.The extracted electrochemical parameters were confirmed via digital simulation.Controlled potential coulometry technique was used for calculation the overall number of electrons involved in electrode reaction.

scholarly journals Electrochemical Investigation of Some Pharmaceutical Compounds at Mercury Electrode

2018 ◽  
Vol 34 (6) ◽  
pp. 2851-2858
Author(s):  
A. A. Al-Owais ◽  
I. S. El-Hallag
Keyword(s):  
Rate Constant ◽  
Digital Simulation ◽  
Supporting Electrolyte ◽  
Mercury Electrode ◽  
Simulation Method ◽  
Electrode Reaction ◽  
Cyclic Voltammograms ◽  
Triazole Derivatives ◽  
Aqueous Buffer ◽  
Electrochemical Parameters

The present work aims to report the investigation of the electrochemical behavior of 3- arylazomethine-1,2,4-triazole derivatives in universal aqueous buffer series at mercury electrode. The electrode behavior of the studied compounds was performed via voltammetric studies, chronoamperometry, convoluted transforms, and dp polarography techniques. The relevant chemical and electrochemical parameters of 3- aryl azomethine -1,2,4- triazole derivatives were determined experimentally in universal aqueous buffer series as supporting electrolyte at mercury electrode. CPC was used for determination of the number of electrons to elucidate the mechanistic pathway of electrode reaction of aryl azomethine triazole compounds. Digital simulation method was used to confirm the accuracy of the experimental chemical parameters (homogeneous chemical rate constant) and electrochemical parameters (heterogeneous rate constant, symmetry coefficient and redox potential) via matching between the experimental and theoretical cyclic voltammograms.

Kinetics of electrode reaction of Eu3+/Eu2+ studied by cyclic voltammetry and tast polarography

1990 ◽  
Vol 55 (7) ◽  
pp. 1666-1672 ◽  
Author(s):  
Jaroslav Němec ◽  
Tomáš Loučka
Keyword(s):  
Cyclic Voltammetry ◽  
Kinetic Parameters ◽  
Electrochemical Behaviour ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Dropping Mercury Electrode ◽  
Sulphate Media ◽  
First Time ◽  
Kinetics Of ◽  
The Eu

The electrochemical behaviour of europium at the dropping mercury electrode was studied in the medium of 1M-NaClO4, 1M-NaCl, 1M-NaNO3, and 1M-Na2SO4. The curves obtained by Tast polarography and the kinetic parameters (ks, α) for the Eu3+/Eu2+ system in the medium of perchlorate and chloride solutions are in accord with the results published earlier. The kinetic parameters in nitrate and sulphate media are given for the first time. In the medium of nitrates, the electrode reaction is probably accompanied by a chemical reaction.

Electrochemical behaviour of 2,5-dihydroxyanisole on a mercury electrode in aqueous media

1989 ◽  
Vol 54 (1) ◽  
pp. 42-52 ◽  
Author(s):  
Dimitra Sazou ◽  
Ioannis Poulios
Keyword(s):  
Oxidation Process ◽  
Electrochemical Behaviour ◽  
Aqueous Media ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Hanging Mercury Drop Electrode ◽  
Electrochemical Investigation ◽  
Basic Solutions ◽  
Ph Range ◽  
Subsequent Chemical

Electrochemical investigation of 2,5-dihydroxyanisole (2,5-DHA) has been carried out in aqueous solutions in pH range 2-11 on hanging mercury drop electrode (HMDE). The oxidation process in pH range 2-6 is a quasi-reversible electrode reaction which involves the transfer of two electrons and two protons. By use of semi-integration a dependence of the heterogeneous rate constant on the potential has been appreciated. Thus, the variation of peak current with pH changes can be explained. In more basic solutions the electrooxidation is complicated by subsequent chemical reactions as indicated from the calculated voltammetric and chronoamperometric parameters.

The Corrosion Study of ZrO2 Coatings on Metals

2007 ◽  
Vol 537-538 ◽  
pp. 247-254 ◽  
Author(s):  
Ioana Rotariu ◽  
Graziella L. Turdean ◽  
Fiammetta Kormos ◽  
Dan Macarovici ◽  
Gyula Tolnai ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Behaviour ◽  
Sol Gel ◽  
Electrochemical Techniques ◽  
Film Morphology ◽  
Protective Layers ◽  
Ph Values ◽  
Electrochemical Parameters ◽  
Steel Substrates

The ZrO2 coatings were deposited by sol-gel techniques on copper and steel. The film morphology has been investigated by AFM technique. The performance of ZrO2 films as protective layers was investigated by electrochemical techniques and optical microscopy. Firstly, the electrochemical behaviour of the uncoated copper and steel substrates was investigated by cyclic voltammetry in HCl (1 M) and NaOH (0.4 M) solutions having various pH values. Secondly, the anticorrosion protective effect of sol-gel ZrO2 coatings was evaluated by potentiodynamic measurements in degrading media in which substrates were immersed for 1-90 days. The comparisons of electrochemical parameters allow an explanation of the role of the ZrO2 coatings in the increased resistance of steel and copper against corrosion in moderately aggressive environments..

Marcus-Hush Theory Revealed by Electron Tunneling Through Hexagonal Boron Nitride

2019 ◽  
Author(s):  
Matěj Velický ◽  
Sheng Hu ◽  
Colin R. Woods ◽  
Peter S. Toth ◽  
Viktor Zólyomi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Boron Nitride ◽  
Electron Tunneling ◽  
Hexagonal Boron Nitride ◽  
Large Body ◽  
Liquid Solution ◽  
Limiting Current ◽  
Electron Transfer Rate Constant ◽  
Electrochemical Parameters ◽  
Voltammetric Measurements

Marcus-Hush theory of electron transfer is one of the pillars of modern electrochemistry with a large body of supporting experimental evidence presented to date. However, some predictions, such as the electrochemical behavior at microdisk electrodes, remain unverified. Herein, we present a study of electron tunneling across a hexagonal boron nitride barrier between a graphite electrode and redox levels in a liquid solution. This was achieved by the fabrication of microdisk electrodes with a typical diameter of 5 µm. Analysis of voltammetric measurements, using two common redox mediators, yielded several electrochemical parameters, including the electron transfer rate constant, limiting current, and transfer coefficient. They show a significant departure from the Butler-Volmer behavior in a clear manifestation of the Marcus-Hush theory of electron transfer. In addition, our system provides a novel experimental platform, which could be applied to address a number of scientific problems such as identification of reaction mechanisms, surface modification, or long-range electron transfer.

scholarly journals Synthesis, Characterization, and Electrochemical Behaviour of Cobalt(II) and Nickel(II) Complexes with N2O2 Chelating Ligand 4,4′-(Biphenyl-4,4′-diyldinitrilo)dipentan-2-one

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Lakhdar Sibous ◽  
Embarek Bentouhami ◽  
Mustayeen Ahmed Khan
Keyword(s):  
Schiff Base ◽  
Mass Spectroscopy ◽  
Elemental Analysis ◽  
Electrochemical Behaviour ◽  
Absolute Ethanol ◽  
Molar Ratio ◽  
H Nmr ◽  
Chelating Ligand ◽  
Metal Ligand

4,4′-Diaminobiphenyl reacts with 2,4-pentanedione in absolute ethanol in a molar ratio 1 : 2 to form mainly the product of [1 + 2] condensation, 4,4′-(biphenyl-4,4′-diyldinitrilo)dipentan-2-one (H2L). The Schiff base was used as tetradentate chelating ligand to coordinate CoII and NiII chlorides leading to complexes where the ratio of metal ligand was found to be 2 : 1 or 2 : 2. All the synthesized products were characterized by elemental analysis, infrared, electronic, and mass spectroscopy, 1H NMR, and DSC. The electrochemical behaviour of the ligand and its complexes in DMF is also investigated.

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