Study of the Electrochemical Redox Characteristics of Some Triazolopyrimidines

Maghraby, A.A. El,Elenien, G.M. Abou,Shehata, K.I. The Korean Electrochemical Society 2007 한국전기화학회지 Vol.10 No.3

An electrochemical study related to the redox characteristics of Ethyl-3-acetyl-6-methyl-1, 4-diphenyl-4, 3a-dihydro-1, 3, 4-triazolino[3, 4-a] pyrimidine-5-carboxylate ester and its derivatives (1a-f) and (2a-e) in nonaqueous solvents such as 1, 2-dichloroethane (DCE), dichloromethane (DCM), acetonitrile (AN), dimethylsulphoxide (DMSO) and tetrahydrofurane (THF) using $0.1\;mol\;dm^{-3}$ tetrabutylammonium perchlorate (TBAP) as a supporting electrolyte at platinum, glassy carbon and gold electrodes, has been performed using cyclic voltammetry (CV). Controlled potential electrolysis (CPE) is also carried out to elucidate the course of different electrochemical reactions through the separation and identification of the intermediates and final electrolysis products. The redox mechanism is suggested and proved. It was found that all the investigated compounds in all solvents are oxidized in a single irreversible one electron donating process following the well known pattern of the EC-mechanism to give a dimer. On the other hand, these compounds are reduced in a single irreversible one electron step to form the anion radical, which is basic enough to proton from the media forming the radical which undergoes tautomerization and then dimerization processes to give also another bis-compound through N-N linkage formation.

Voltammetric Studies on Some Thiadiazoles and Their Derivatives

A.A.El Maghraby 한국전기화학회 2009 한국전기화학회지 Vol.12 No.1

The redox characteristics of 2-arylaldehydehydrazono-3-phenyl-5-substituted-2,3-dihydro- 1,3,4-thiadiazoles (1a-h) have been investigated in nonaqueous solvents such as 1,2-dichloroethane (DCE), dichloromethane (DCM), acetonitrile (AN), Tetrahydrofuran (THF), and dimethylsulfoxide (DMSO) at platinum electrode. Through controlled potential electrolysis, the oxidation and reduction products of the investigated compounds had been separated and indentified. The redox mechanism had been suggested and proved. It had been found that all the investigated compounds were oxidized in two irreversible one-electron processes following the well-known pattern of The EC-mechanism; the first electron loss gives the corresponding cation- radical which is followed by proton removal from the ortho-position in the N-phenyl ring forming the radical. The obtained radical undergoes a second electron uptake from the nitrogen in the N = C group forming the unstable intermediate (di-radical cation) which undergoes ring closure forming the corresponding cation. The formed cation was stabilized in solution through its combination with a perchlorate anion from the medium. On the other hand, these compounds are reduced in a single two-electron process or in a successive two one-electron processes following the well known pattern of the EEC-mechanism according to the nature of the substituent; the first one gives the anion-radical followed by a second electron reduction to give the dianion which is basic enough to abstract protons from the media to saturate the (C = O) bond.

Voltammetric Studies on Some Thiadiazoles and Their Derivatives

Maghraby, A. A. El,Abou-Elenien, G. M.,Rateb, N. M,Abdel-Tawab, H. R. The Korean Electrochemical Society 2009 한국전기화학회지 Vol.12 No.1

The redox characteristics of 2-arylaldehydehydrazono-3-phenyl-5-substituted-2, 3-dihydro-1, 3, 4-thiadiazoles (1a-h) have been investigated in nonaqueous solvents such as 1, 2-dichloroethane (DCE), dichloromethane (DCM), acetonitrile (AN), Tetrahydrofuran (THF), and dimethylsulfoxide (DMSO) at platinum electrode. Through controlled potential electrolysis, the oxidation and reduction products of the investigated compounds had been separated and indentified. The redox mechanism had been suggested and proved. It had been found that all the investigated compounds were oxidized in two irreversible one-electron processes following the well-known pattern of The EC-mechanism; the first electron loss gives the corresponding cation-radical which is followed by proton removal from the ortho-position in the N-phenyl ring forming the radical. The obtained radical undergoes a second electron uptake from the nitrogen in the N = C group forming the unstable intermediate (di-radical cation) which undergoes ring closure forming the corresponding cation. The formed cation was stabilized in solution through its combination with a perchlorate anion from the medium. On the other hand, these compounds are reduced in a single two-electron process or in a successive two one-electron processes following the well known pattern of the EEC-mechanism according to the nature of the substituent; the first one gives the anion-radical followed by a second electron reduction to give the dianion which is basic enough to abstract protons from the media to saturate the (C = O) bond.

몇 가지 치환 Thiadiazole에 대한 전기화학적 연구

El Maghraby, A. A.,Abou-Elenien, G. M.,Abdel-Reheem, N. A.,Abdel-Tawab, H. R. 대한화학회 2006 대한화학회지 Vol.50 No.4

2-Ketohydrazono-3-phenyl-5-substituted-2,3-dihydro-1,3,4-thiadiazole과 그 유도체들(1a-h)의 산화환원 특성을 백금 전극의 지지전해질로서 0.1 M tetra n-butylammonium perchlorate (TBAP)을 함유한 1,2-dichloroethane (DCE), dichloromethane (DCM), acetonitrile (AN), tetrahydrofuran (THF), and dimethylsulfoxide (DMSO)와 같은 비수용매 속에서 조사하였다. 조사한 화합물들의 산화 및 환원 생성물들을 조절전위 전해법으로 분리 확인하였으며, 산화환원 메커니즘을 제안하고 이를 증명하였다. 조사한 모든 화합물은 잘 알려진 EC 메커니즘에 이은 두 번의 비가역 일전자 과정에 의해 산화되는 반면, 환원의 경우에는 치환기의 성질에 따라, 잘 알려진 EEC 메커니즘에 이은 한번의 이전자 또는 두 번의 연속적인 일전자 과정에 의해 이루어짐을 알았다. The redox characteristics of 2-ketohydrazono-3-phenyl-5-substituted-2,3-dihydro-1,3,4-thiadiazoles and its derivatives (1a-h) has been investigated in nonaqueous solvents such as 1,2-dichloroethane (DCE), dichloromethane (DCM), acetonitrile (AN), tetrahydrofuran (THF), and dimethylsulfoxide (DMSO) containing 0.1 mol.dm-3 tetra n-butylammonium perchlorate (TBAP) as supporting electrolyte at platinum ectrode. Through controlled potential electrolysis, the oxidation and reduction products of the investigated compounds can be separated and indentified. The redox mechanism is suggested and proved. It was found that all the investigated compounds are oxidized in two irreversible one-electron processes following the well known pattern of EC-mechanism. On the other hand, these compounds are reduced in a single two electron or in a successive two one electron processes following the well known pattern of EEC-mechanism according to the nature of the substituent

Study of the Electrochemical Redox Characteristics of Some Triazolopyrimidines

A. A. El Maghraby,G. M. Abou Elenien,K. I. Shehata 한국전기화학회 2007 한국전기화학회지 Vol.10 No.3

Equilibrium and kinetic studies for the removal of cationic dye using banana pith

El-Maghraby, Azza,Taha, Nahla A. Techno-Press 2014 Advances in environmental research Vol.3 No.3

The large quantity of green cull bananas has the potential of being used industrially and, thereby, to improve banana economics and eliminate the large environmental problem presented by banana waste. Wastewaters from textile, cosmetics, printing, dying, food colouring, and paper-making industries are polluted by dyes. The adsorption of basic dye by waste banana pith was investigated by varying dye concentrations, adsorbent dose, particle size and agitation rate. The adsorption capacity was found to be maximum value of removal by using 0.1 g of sorbent with particle size 1mm at mixing speed 200 rpm for initial concentration 25 mg/l to reach value of approximate 89%. The Langmuir, Temkin and Freundlich adsorption models were used for mathematical description of the adsorption equilibrium and it was found that experimental data fitted very well to these models except Langmuir model. Adsorption of dye was applied on (pseudo-first and pseudo-second-order kinetics), and the experimental data was more fitted to pseudo second order. The results of this study showed that banana pith could be employed as effective and low-cost materials for the removal of dyes from aqueous solutions.

Cu₀- doped TiO₂ nanofibers as potential photocatalyst and antimicrobial agent

Yousef, A.,El-Halwany, M.M.,Barakat, N.A.M.,Al-Maghrabi, M.N.,Kim, H.Y. Korean Society of Industrial and Engineering Chemi 2015 Journal of industrial and engineering chemistry Vol.26 No.-

Cu<SUB>0</SUB> nanoparticles (NPs)-doped TiO<SUB>2</SUB> nanofibers (NFs) were prepared as an effective photodegradation of three azo dyes as well as an antimicrobial agent under visible light. Fabrication of one dimensional zero-valent Cu nanoparticles-doped TiO<SUB>2</SUB> nanofibers with high aspect ratio have been successfully synthesized by simple and low cost; electrospinning technique followed by hydrothermal process. The photocatalytic activity of introduced nanofibers was evaluated by performing of three azo dyes. Catalytic NFs show a superior photodegaradation activity under visible light as well as good antimicrobial activity. Moreover, photocatalyst nanofibers appeared good stability, which was used for three cycles without regeneration.

Research Articles : Diversity of Keratinophilic Fungi on Human Hairs and Nails at Four Governorates in Upper Egypt

( Youssuf A. M. H. Gherbawy ),( Thanaa A. Maghraby ),( Hassan M. El Sharony ),( Mohmaed A. Hussein ) 한국균학회 2006 Mycobiology Vol.34 No.4

Oscillation and nonoscillation of nonlinear second order difference equations}

M. M. A. EL-Sheikh,M. H. Abd Alla,E. M. EL-Maghrabi 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.21 No.1-2