scholarly journals 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

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.

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

2011 ◽  
Vol 7 (1) ◽  
pp. 1271-1279
Author(s):  
Omar A. Hazazi ◽  
Refat El-Sayed ◽  
El-Sayed. M. Mabrouk
Keyword(s):  
Reaction Pathway ◽  
Aqueous Media ◽  
Reduction Process ◽  
Electrode Reaction ◽  
Azo Compounds ◽  
Controlled Potential ◽  
Voltammetric Studies ◽  
Electron Reduction ◽  
Amine Compounds ◽  
Controlled Potential Coulometry

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.

scholarly journals Electrochemical Behaviour of N′-(p-toluenesulphonyl)-3-methyl-4-(4′-substituted arylhydrazono) pyrazolin-5-ones

2012 ◽  
Vol 9 (4) ◽  
pp. 1864-1874
Author(s):  
V. Nagaraju ◽  
R. Sreenivasulu ◽  
P. Venkata Ramana
Keyword(s):  
Electrochemical Behaviour ◽  
Reduction Process ◽  
Effect Of Solvent ◽  
Buffer Solutions ◽  
Diffusion Controlled ◽  
Controlled Potential Electrolysis ◽  
Dc Polarography ◽  
Controlled Potential ◽  
Ph Range ◽  
And Diffusion

The electrochemical behaviour of N′-(p-toluenesulphonyl)-3-methyl-4-(4′-substituted arylhydrazono) pyrazolin-5-ones has been investigated at dme and gc electrodes in buffer solutions of pH 2.0, 4.0, 6.0, 8.0 and 10.0 using dc polarography and cyclic voltammetry and coulometry. The compounds exhibit one well defined wave in the entire pH range of study. The process is irreversible and diffusion controlled. Controlled potential electrolysis indicates the involvement of four electrons in the reduction process. The effect of solvent, cations and anions, temperature and substitutents on the mechanism of reduction has been studied. Based on the results obtained the mechanism of reduction has been suggested.

Structure, absolute configuration and electrochemical properties of Tris(N-methylformothiohydroxamato)iron(III), an antibacterial metal chelate and potential iron siderochrome

1978 ◽  
Vol 31 (5) ◽  
pp. 983 ◽  
Author(s):  
KS Murray ◽  
PJ Newman ◽  
BM Gatehouse ◽  
D Taylor
Keyword(s):  
Absolute Configuration ◽  
Title Compound ◽  
Metal Chelate ◽  
Octahedral Complex ◽  
Reduction Wave ◽  
Irreversible Reduction ◽  
Distorted Octahedral ◽  
Voltammetric Studies ◽  
Dispersion Technique ◽  
Cyclic Voltammetric Studies

The title compound, which previously had been isolated from bacteria and shown to possess anti-bacterial activity, has been chemically synthesized. The molecular structure has a cis (facial) arrangement of the asymmetric {S,O} bidentate ligands (Fe-S 2.441(1) Ǻ, Fe-O 2.010(1) Ǻ) as required by the crystallographic C3 molecular symmetry. (Crystal data: C6H12N3O3S3Fe, rhombohedral, space group R3, a 7.094(2)Ǻ, α 102.00(1)°, Z 1.) The complex was spontaneously resolved into enantiomers on crystallization and the absolute configuration in the crystal studied was established as Λ by the anomalous dispersion technique. Magnetic, e.s.r. and Mossbauer studies are compatible with a distorted octahedral complex of high-spin iron(III). Cyclic voltammetric studies in acetone of the title compound and some related iron(III) thiohydroxamates were carried out. A reversible FeIII/FeII reduction wave was observed for the N-methylformothiohydroxamato chelate, in contrast to the irreversible reduction of tris(benzohydroxamato)iron(III), a related complex containing an {O,O} chelate. The tris(benzothiohydroxamato) chelate, Fe(PhC(S)NHO)3, which possesses a non-alkylated nitrogen, also showed an irreversible reduction wave.

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.

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