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.

scholarly journals Differential Pulse Polarographic Determination of Procymidone in Formulations and Wine

2002 ◽  
Vol 85 (3) ◽  
pp. 731-735 ◽  
Author(s):  
Neelam Y Sreedhar ◽  
Thommandru R Babu ◽  
Kethamreddy Samatha ◽  
Devarapalli Sujatha ◽  
Thenepalli Thriveni
Keyword(s):  
Reduction Process ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Experimental Conditions ◽  
Controlled Potential Electrolysis ◽  
Pulse Polarography ◽  
Half Wave ◽  
Single Well ◽  
Controlled Potential ◽  
Ph Range

Abstract The dicarboximide fungicide procymidone was studied systematically by using direct current polarography, cyclic voltammetry, differential pulse polarography (DPP), controlled potential electrolysis, and millicoulometry in the universal buffer medium with dimethylformamide as the solvent. Procymidone exhibited a single well-defined polarographic wave in the pH range 2.0–6.0, leading to the formation of the hydroxy compound. The overall reduction process was diffusion-controlled and adsorption-free. The variation of half-wave potential with pH, the concentration of the analyte, and other experimental conditions are described. The reduction mechanism proposed is an overall 4-electron process, in which the dicarboximide group is reduced. DPP was used to determine procymidone in agricultural formulations and wine at the optimum conditions found; a detection limit of 2.4 × 10−9M was estimated. The results obtained by the proposed method were also compared with those obtained by other methods.

The electrochemical oxidation of 2,5-dihydroxybenzoic acid on a mercury electrode in aqueous solutions

1986 ◽  
Vol 64 (1) ◽  
pp. 11-14 ◽  
Author(s):  
D. Sazou ◽  
N. Papadopoulos
Keyword(s):  
Oxidation Process ◽  
Electrochemical Behaviour ◽  
Mercury Electrode ◽  
The Other ◽  
Hanging Mercury Drop Electrode ◽  
Dihydroxybenzoic Acid ◽  
Current Function ◽  
Controlled Potential Electrolysis ◽  
Controlled Potential ◽  
Ph Range

The electrochemical behaviour of 2,5-dihydroxybenzoic acid (2,5-DHBA) has been studied in the pH range 5.5–12.7 at a hanging mercury drop electrode (HMDE). Voltammograms show the existence of one reversible wave of 2,5-DHBA governed by diffusion conditions. In the oxidation process a two-electron transfer takes place, as shown by the controlled potential electrolysis. From the calculation of the voltammetric parameters (peak width Ep − Ep/2, peak current function [Formula: see text]and from the other experimental data, a mechanism for the overall reaction in two different pH ranges, 5.5–9.5 and 9.5–12, is proposed.

VOLTAMMETRIC DETERMINATION OF ACETOPHOS IN WATER SAMPLES AT CNTPE

2013 ◽  
Vol 12 (03) ◽  
pp. 1350018
Author(s):  
SARVAREDDY RAJASEKHAR REDDY ◽  
T. RAVEENDRANATH BABU
Keyword(s):  
Water Samples ◽  
Supporting Electrolyte ◽  
Reduction Process ◽  
Standard Addition ◽  
Differential Pulse ◽  
Experimental Conditions ◽  
Controlled Potential Electrolysis ◽  
Universal Buffer ◽  
Controlled Potential ◽  
Ph Range

In this paper, a sensitive differential pulse voltammetric method to determine the residues of acetophos in water samples at CNTPE were reported. The significance of CNTPE is to result in low detection limits, high sensitivities, reduction of over-potentials, high mechanical strength and high conductivity and resistance to surface fouling. The universal buffer with pH range 2.0–6.0 is used as supporting electrolyte. Cyclic voltammetry employed to evaluate electrode mechanism and number of electrons involved in reduction process were found out by using Millicoulometry and the product collected by applying Controlled potential electrolysis. Experimental conditions such as accumulation potential, accumulation time and scan rate were optimized. Calculations were made by standard addition method.

Synthesis and electroreduction of 2-[(8-hydroxyquinoline-5-yl)azo]benzo[c]cinnoline in DMSO–H2O (1:1) medium

2010 ◽  
Vol 75 (11) ◽  
pp. 1201-1216
Author(s):  
Funda Öztürk ◽  
Zehra Durmuş ◽  
Öznur Ölmez Uçkan ◽  
Emine Kiliç ◽  
Esma Kiliç
Keyword(s):  
Reaction Diffusion ◽  
Electrode Reaction ◽  
Basic Medium ◽  
Cyclic Voltammograms ◽  
H Nmr ◽  
Controlled Potential Electrolysis ◽  
Controlled Potential ◽  
Constant Potential ◽  
Ph Range ◽  
Tlc Analysis

2-[(8-Hydroxyquinoline-5-yl)azo]benzo[c]cinnoline (HQAB) was prepared and characterized by elemental analysis, MS, FTIR and 1H NMR techniques. The electrochemical reduction of HQAB has been investigated by cyclic voltammetry, chronoamperometry and controlled potential electrolysis at mercury pool electrode in the pH range 3.5–9.4. The number of electrons transferred in the electrode reaction, diffusion coefficients and standart rate constants were calculated. In acidic medium, cyclic voltammograms display four cathodic peaks, with the total exchange of 6 e– and 6 H+. By contrast, the reverse scan displays two anodic peaks. Constant potential electrolysis at –1.0 V and TLC analysis of the product reveals that the reduction of azo group (in the bridge) in HQAB does not stop at the hydrazo stage but goes further through the cleavage of –NH–NH– linkage to give amino compounds as the final products. The voltammograms recorded in basic medium exhibit two cathodic peaks corresponding to 4 e–, 4 H+ and two reverse anodic peaks, and thus the reduction stopped at hydrazo stage. A tentative mechanism for the reduction has been suggested.

Electrochemical investigations on some potential antibacterials, I

1995 ◽  
Vol 73 (2) ◽  
pp. 176-180 ◽  
Author(s):  
Rajeev Jain ◽  
M. Damodharan
Keyword(s):  
Cyclic Voltammetry ◽  
Glassy Carbon ◽  
Electrochemical Behaviour ◽  
Carbon Electrodes ◽  
Electron Wave ◽  
Nmr Studies ◽  
Glassy Carbon Electrodes ◽  
Single Well ◽  
Controlled Potential ◽  
Ph Range

Electrochemical behaviour of the medicinally important 4-(4′-sulphonamoyl)hydrazono-1-phenyl-3-methyl-2-pyrazolin-5-ones has been studied at d.m.e. and glassy carbon electrodes. At d.m.e., all six compounds exhibited a single, well-defined, four-electron wave in the pH range 2.5–12.0. Polarographic four-electron wave was found to be diffusion-controlled and irreversible. Similarly, cyclic voltammetry of these compounds at glassy carbon electrode exhibited a single peak. Peak potential shows shifts towards negative potential with pH, with linear segments up to pH 8.2 and are practically pH independent at higher pH values. An anodic peak at far-off positive potential was observed in the reverse scan, indicating the irreversible nature of the electrode process. Controlled potential electrolysis and coulometric studies gave the value of n as 4.0 ± 0.1 in the pH range 2.5 to 10.0. Out of the two major end products formed, one was identified as sulphanilamide and the other as 1-phenyl-3-methyl-4-amino-2-pyrazolin-5-one on the basis of IR and NMR studies. On the basis of DCP, LSV, CV, CPE, coulometry and spectral analysis, a mechanism has been postulated for the reduction of these compounds at d.m.e. and glassy carbon electrodes. Keywords: polarography, cyclic voltammetry, antibacterials, pyrazolin-5-ones.

Electrochemical studies of amine salts of monothiocarbamates

1982 ◽  
Vol 35 (12) ◽  
pp. 2465
Author(s):  
RJ Magee ◽  
B Annuar
Keyword(s):  
Electrochemical Behaviour ◽  
Mercury Electrode ◽  
Compact Layer ◽  
Cyclic Voltammetric ◽  
Reactive Material ◽  
Anodic Wave ◽  
Diffusion Controlled ◽  
Controlled Potential ◽  
Controlled Potential Coulometry ◽  
Amine Salts

The electrochemical behaviour of the amine salts of morpholyl-, pyrrolidyl-�and piperidyl-mono- thiocarbamates (morpholinium morpholine-4-carbothioate, piperidinium piperidine-1-carbothioate and pyrrolidinium pyrrolidine-1-carbothioate) at the mercury electrode has been studied by means of d.c. polarography and cyclic voltammetry. All three exhibited a well defined anodic wave, but the pyrrolidyl derivative (pymtc) gave an additional wave. The main wave in each case was found to be diffusion-controlled. Temperature coefficients showed erratic behaviour at higher temperatures which was thought to be due to decreasing availability of reactive material because of decomposition. Controlled potential coulometry gave n = 1 per mole for the main wave of each compound. The behaviour was similar to that of the dithiocarbamate ligands under the same conditions and the small pre-wave in the polarograms of pymtc is attributed to the formation of a mercuric pyrrolidyl monothiocarbamate, which, unlike the mercuric complex of the other two ligands is structurally ordered and able to form a compact layer with the electrode. Cyclic voltammetric results supported the findings of polarography and confirmed the following mechanism: mtc- + Hg → Hg(mtc) + e' (1) 2Hg(mtc) → Hg(mtc)2 + Hg (2)

scholarly journals Electrochemical behavior and differential pulse voltammetric determination of ceftazidime, cefuroxime-axetil and ceftriaxone

2013 ◽  
Vol 11 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Mara Aleksic ◽  
Nikola Lijeskic ◽  
Jelena Pantic ◽  
Vera Kapetanovic
Keyword(s):  
Reduction Process ◽  
Differential Pulse ◽  
Cefuroxime Axetil ◽  
Pharmaceutical Dosage Forms ◽  
Diffusion Controlled ◽  
Voltammetric Behavior ◽  
Pulse Voltammetry ◽  
Ph Range ◽  
Linear Concentration

The voltammetric behavior of three cephalosporins: ceftazidime, cefuroxime-axetil and ceftriaxone has been examined in pH range 2.0-8.0 by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), using a hanging mercury drop electrode (HMDE). The effect of pH of the electrolyte solution and scan rate on the peak currents and peak potentials was examined. The nature of the electrode reduction process in acid solution was found to be diffusion controlled for ceftazidime and cefuroxime-axetil, but strongly influenced by adsorption in the case of ceftriaxone reduction. The adsorption and reorientation of the ceftriaxone molecule at the electrode surface caused instability of the voltammetric signal and disabled its determination in the acid medium. Ceftriaxone adsorption decreased with the increase of pH, and at pH>7 the reduction process became diffusion controlled. Based on this study, DPV method was developed, validated and suggested for determination of ceftazidime at pH 2.0, cefuroxime-axetil at pH 3.5 and for ceftriaxone at pH 8.0. Linear concentration ranges, limits of detection (LOD) and quantification (LOQ) were determined. The method was applied for determination of cephalosporins in pharmaceutical dosage forms: Ceftazidime powder, Ceroxim tablets and Longaceph powder for injection solution.

Electrochemical investigation of some potential antibacterials, II

1997 ◽  
Vol 75 (5) ◽  
pp. 567-574 ◽  
Author(s):  
Rajeev Jain ◽  
P. Padmaja ◽  
Seema Gupta
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Behaviour ◽  
Reduction Reaction ◽  
Carbon Electrodes ◽  
Reduction Wave ◽  
Electrochemical Investigation ◽  
Glassy Carbon Electrodes ◽  
Controlled Potential Electrolysis ◽  
Wide Range ◽  
Controlled Potential

The electrochemical behaviour of 2-(4′-sulphonamoyl)hydrazonobutyrate-1,3-diones and sulphonamoylazoaminobenzenes has been studied over a wide range of pH at dropping mercury as well as glassy carbon electrodes. Both types of compounds exhibited a 4e− reduction reaction at both electrodes. At pH > 4.5, 2-(4′-sulphonamoyl)hydrazonobutyrate-1,3-diones exhibited a 2e− reduction wave at higher potentials. Both compounds undergo a 2e− oxidation reaction. On the basis of polarography, linear and cyclic voltammetry, controlled potential electrolysis, coulometry, and spectral analysis, a detailed mechanism has been postulated for the reduction as well as the oxidation. Keywords: electrochemistry, sulphonamides, polarography, cyclic voltammetry, coulometry.

Electrochemical behaviour of some alkyl substituted N-hydroxy-2,6-diarylpiperidin-4-one thiosemicarbazone and the antifungal studies of the products

2017 ◽  
Vol 13 (9) ◽  
pp. 6445-6455
Author(s):  
J B Veeramalini ◽  
G Baskar ◽  
N. Sheeja
Keyword(s):  
Electrochemical Behaviour ◽  
13C Nmr Spectroscopy ◽  
1H And 13C Nmr ◽  
Cyclic Voltammetric Study ◽  
Diffusion Controlled ◽  
Reduced Products ◽  
Acidic Conditions ◽  
Anti Fungal ◽  
And Diffusion ◽  
High Inhibition

A series of 3-ethyl-2,6-diarylpiperidin-4-one thiosemicarbazone and 3,5-dimethyl-2,6-diarylpiperidin-4-one thiosemicarbazone were synthesised. The thiosemicarbazones were subjected to cyclic voltammetric study using graphite electrode with variable scan rate at moderate acidic conditions maintained in the electrolytic solution. The reduction takes place by two electron transfer and the reaction is pH dependent. The reduced products were isolated and purified by column chromatography. The structure was proved by 1H and 13C NMR spectroscopy. The electrode process was found to be irreversible and diffusion controlled. Further the products were analysed for anti fungal activity in which nitro substituted compound showed high inhibition towards the fungi Asperillus niger

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