Voltammetric studies of some azo compounds derived from 4-methyl-6,7-dihydroxy coumarin in microemulsion and aqueous media

The cyclic voltammetric(CV) behavior of some azo compounds based on coumarin derivatives was investigated in microemulsion systems and in aqueous solutions. The obtained results indicated that these compounds undergo an irreversible 4-electron reduction step leading to cleavage of the N=N center with the formation of amine compounds in all media. The effect of medium on the CV parameters was discussed. The total number of electrons involved in the reduction process was determined by controlled potential coulometry. Also, The effect of substituents on the electrode reaction pathway and the kinetic parameters of the electrode process were calculated and discussed. Based on the data obtained the electroreduction mechanism was suggested and discussed.

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DC-polarography and cyclic voltammetric studies of some mono and bis azo compounds derived from aromatic primary amines and 2,3-dihydroxynaphthalene in aqueous solutions

Material Science Research India ◽

10.13005/msri/070203 ◽

2010 ◽

Vol 7 (2) ◽

pp. 339-346

Author(s):

R. El-Sayed ◽

AbdAllah A. Mohamed ◽

E. M. Mabrouk

Keyword(s):

Reduction Process ◽

Azo Compounds ◽

Primary Amines ◽

Alkaline Solutions ◽

Irreversible Reduction ◽

Dc Polarography ◽

Controlled Potential ◽

Voltammetric Studies ◽

Amine Compounds ◽

Cyclic Voltammetric Studies

The DC and CV behavior of some mono and bis azo compounds based on aromatic primary amines and 2,3-dihydroxynaphthalein was investigated in Britton-Robinson buffer series. The obtained results indicated that these compounds undergo an irreversible reduction leading to cleavage of the N=N center with the formation of amine compounds. However, for the derivative m-CH3 on the aniline ring in alkaline solutions, the reduction stops at the stage for saturation of the N=N center. The E1/2 and Ep shifted to more negative potentials with rise of pH and the values of il are not much influenced except for the m-CH3 derivative. The total number of electrons involved in the reduction process was determined by controlled potential coulomety and calculated from Ilkovic equation. The effect of substituents on the electrode pathway was discussed. Based on the data obtained the electroreduction mechanism was suggested and discussed.

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Effect of ligand structure, solvent, and temperature on the electrochemical behavior of polyarene–iron complexes

Canadian Journal of Chemistry ◽

10.1139/v96-070 ◽

1996 ◽

Vol 74 (5) ◽

pp. 650-657 ◽

Cited By ~ 13

Author(s):

Alaa S. Abd-Ei-Aziz ◽

Christine R. De Denus ◽

Karen M. Epp ◽

Simone Smith ◽

Richard J. Jaeger ◽

...

Keyword(s):

Reduction Process ◽

Iron Complexes ◽

Electrochemical Investigation ◽

Dissociative Mechanism ◽

Bridging Ligand ◽

Controlled Potential ◽

Degree Of Stability ◽

Arene Ligand ◽

Redox Centers ◽

Controlled Potential Coulometry

The electrochemical investigation of a number of polyarene–iron complexes ([3]2+–[9]5+) containing etheric, sulphide, and sulphone bridges indicated that there were various degrees of interaction based on the nature of the bridging heteroatoms. While the electrochemical investigation of all etheric complexes showed that the metallic moieties behaved as isolated redox centers, it was found that there was electronic communication (ca. 70–80 mV) for the isomeric sulphide complexes [4]2+ and [6]2+. The rate constant of the following chemical reaction (kf) was calculated for some of these complexes and it was found that these rates were affected by the nature of the solvent, the bridging ligand, and the temperature. At various temperatures, kf indicated a higher degree of stability for complexes containing sulphide bridges than for those containing etheric bridges, especially at room temperature. The effect of a strong coordinating solvent, such as acetonitrile, on the kf of complex [3]2+ indicated that the substitution of the arene ligand with acetonitrile molecules proceeded as a dissociative mechanism. Controlled potential coulometry was also used to verify the transfer of two electrons in the first reduction process of the di-iron complexes. Key words: cyclopentadienyliron, cyclic voltammetry, arene complexes, isolated and interacting redox centers.

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

JOURNAL OF ADVANCES IN CHEMISTRY ◽

10.24297/jac.v14i1.6316 ◽

2017 ◽

Vol 14 (1) ◽

pp. 6021-6032 ◽

Cited By ~ 2

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 â€“ ligand formation constants were determined potentiometrically and found in the order CuËƒ CoËƒ Ni ËƒZn.

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

Canadian Journal of Chemistry ◽

10.1139/v97-122 ◽

1997 ◽

Vol 75 (7) ◽

pp. 1023-1029 ◽

Cited By ~ 8

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.

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A novel Kolbe reaction pathway for a selective one- and two-electron reduction of azo compounds

Chemical Communications ◽

10.1039/b906910k ◽

2009 ◽

pp. 5524 ◽

Cited By ~ 6

Author(s):

Wen-Fu Fu ◽

Huifang-Jie Li ◽

De-Hui Wang ◽

Liang-Jun Zhou ◽

Li Li ◽

...

Keyword(s):

Reaction Pathway ◽

Azo Compounds ◽

Kolbe Reaction ◽

Electron Reduction

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Voltammetric Studies of Anthracen-9-ylmethylene-(3,4-dimethyl-isoxazol-5-yl)-amine Compound at Platinium Electrode

Journal of New Materials for Electrochemical Systems ◽

10.14447/jnmes.v18i3.366 ◽

2015 ◽

Vol 18 (3) ◽

pp. 177-181 ◽

Cited By ~ 1

Author(s):

A. A. Al-Owais ◽

I. S. El-Hallag

Keyword(s):

Cyclic Voltammetry ◽

Radical Cation ◽

Reaction Pathway ◽

Digital Simulation ◽

Electrode Reaction ◽

Simulation Techniques ◽

Electrochemical Parameters ◽

Voltammetric Behavior ◽

Voltammetric Studies

The voltammetric behavior of anthracen-9-ylmethylene-(3,4-dimethyl-isoxazol-5-yl)-amine compound at Platinium electrode has been performed via convolutive cyclic voltammetry and digital simulation techniques using a conventional platinium electrode in 0.1 mol L-1 tetrabutylammonium perchlorate (TBAP) in acetonitrile solvent (CH3CN). The compound loss one electron forming radical cation followed by fast chemical step and the radical cation loss another two electrons producing trication which followed by chemical reaction (ECEC). Cyclic voltammetry and convolutive voltammetry were used for determination of the chemical and the electrochemical parameters of the electrode reaction pathway of the investigated compound. The Electrochemical parameters such as α, ks, Eo , D, and kc of the investigated isoxazol derivative were verified via digital simulation technique. Voltammetric studies of the investigated isoxazol derivative compound under consideration was presented and discussed.

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Electrochemical Reduction of 1-Halo-2-butenes in Dimethylformamide

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19932875 ◽

1993 ◽

Vol 58 (12) ◽

pp. 2875-2890 ◽

Cited By ~ 1

Author(s):

Juan Casado ◽

José R. Culleré ◽

Montserrat Julià ◽

Enrique Brillas

Keyword(s):

Electrochemical Reduction ◽

Gold Electrode ◽

Ring Electrode ◽

Allyl Radical ◽

Rate Determining Step ◽

Ec Mechanism ◽

Controlled Potential ◽

Electron Reduction ◽

Controlled Potential Coulometry ◽

Rotating Ring Disc Electrode

The electrochemical reduction of 1-bromo-2-butene and 1-chloro-2-butene in DMF at a Hg electrode has been studied by polarography, cyclic voltammetry (CV), a rotating ring-disc electrode and controlled-potential coulometry. A CV study using a gold electrode has also been carried out for these compounds to identify the detected intermediates. Two consecutive one-electron reduction processes are found for 1-bromo-2-butene in polarography and in CV using Hg electrode. The first process is initiated by the irreversible one-electron cleavage of the carbon-bromo bond to give the allyl radical and Br-, which is the rate-determining step. The second one follows a first-order EC mechanism, being initiated by generation of the allylmercury anion via a one-electron reduction of the allylmercury radical, previously formed by reaction of the allyl radical with Hg. A single irreversible two-electron process is found for 1-chloro-2-butene under all voltammetric conditions and for both compounds in CV using a gold electrode. Additional anodic peaks detected in CV, as well as anodic waves found at the rotating Hg ring electrode, are ascribed to oxidation of the allylmercury anion and the allyl anion.

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Voltammetric and potentiometric studies of some sulpha drug-Schiff base compounds and their metal complexes

Open Chemistry ◽

10.2478/s11532-007-0035-7 ◽

2007 ◽

Vol 5 (3) ◽

pp. 898-911 ◽

Cited By ~ 1

Author(s):

M. Ghoneim ◽

E. Mabrouk ◽

A. Hassanein ◽

M. El-Attar ◽

E. Hesham

Keyword(s):

Schiff Bases ◽

Reaction Pathway ◽

Mercury Electrode ◽

Transition Metal Ions ◽

Electrode Reaction ◽

Cyclic Voltammograms ◽

Azomethine Group ◽

Sulpha Drug ◽

Controlled Potential ◽

The Stability

AbstractThe electrochemical behavior of some sulpha drug-Schiff bases at a mercury electrode was examined in the Britton-Robinson universal buffer of various pH values (2.5–11.7) containing 20% v/v) of ethanol using DC-polarography, cyclic voltammetry and controlled-potential electrolysis. The DC-polarograms and cyclic voltammograms of the examined compounds exhibited a single, 2-electron, irreversible, diffusion-controlled cathodic step within the entire pH range which is attributed to the reduction of the azomethine group-CH=N- to -CH2-NH-. The symmetry transfer coefficient (α) of the electrode reaction and the diffusion coefficient (D 0) of the reactant species were determined. The electrode reaction pathway of the compounds at the mercury electrode was suggested to follow the sequence: H+, e−, e−, H+. The dissociation constant of the sulpha drug-Schiff bases, the stability constant and stoichiometry of their complexes with various divalent transition metal ions (Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) were determined potentiometrically at room temperature.

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