Search for: catechols
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    Thermodynamic studies on the complexation of cobalt(II) with dopamine in a cosolvent system

    , Article Journal of Solution Chemistry ; Volume 36, Issue 5 , 2007 , Pages 595-604 ; 00959782 (ISSN) Bagheri, A ; Boghaei, D. M ; Sharif University of Technology
    Equilibrium constants for formation of a cobalt(II) complex with the bidentate ligand dopamine have been studied with spectrophotometric methods in water + ethanol cosolvent systems at 15, 25, and 35 (±0.1)∈°C and an ionic strength of 0.2 mol·dm-3. The ionic strength was maintained using sodium chloride and a phosphate buffer. The stability constants of the complex and the resulting Gibbs energy changes are obtained. The results are discussed in terms of the effect of solvent on protonation and complexation. © Springer Science+Business Media, LLC 2007  

    Electrochemical functionalization of graphene nanosheets with catechol derivatives as an effective method for preparation of highly performance supercapacitors

    , Article Electrochimica Acta ; Vol. 147, issue , 2014 , pp. 136-142 ; ISSN: 00134686 Jokar, E ; Shahrokhian, S ; Zad, A. I ; Sharif University of Technology
    Performance enhancement of supercapacitors has been recently discussed. In this paper a novel and facile procedure for functionalization of graphene with some electroactive molecules is presented. The graphene has been functionalized by catechol-based molecules, which are electroactive molecules with electrochemically reversible properties. The functionalized graphene exhibits very effective pseudocapacitor behaviorfor charge storage. For the first time, with the aim of an electrosynthesis procedure, catechol is covalently attached on graphene sheets. This attachment has been investigated by electrochemical, X-ray photoelectron spectroscopy and attenuated total reflectance methods. Catechol... 

    Electrochemical oxidation of catechol in the presence of 2-thiouracil: Application to electro-organic synthesis

    , Article Electrochemistry Communications ; Volume 5, Issue 8 , 2003 , Pages 706-710 ; 13882481 (ISSN) Shahrokhian, S ; Hamzehloei, A ; Sharif University of Technology
    Elsevier Inc  2003
    The electrochemical oxidation of catechol in the presence of 2-thiouracil (as a nucleophile) has been studied in aqueous solutions using cyclic voltammetry and controlled-potential coulometric techniques. The results indicate that catechol participating in a 1,4 (Michael) addition reaction converts to a new thiadiazafluorenone compound. The electrochemical synthesis of this compound has been successfully performed in an undivided cell in a good yield and purity and was characterized by IR, 1H and 13C NMR, mass spectrometry and elemental analysis. © 2003 Published by Elsevier B.V  

    Differential pulse voltammetric determination of propylthiouracil and methylthiouracil using their catalytic effects on the electrochemical oxidation of catechol

    , Article International Journal of Electrochemical Science ; Volume 2, Issue 2 , 2007 , Pages 158-168 ; 14523981 (ISSN) Shahrokhian, S ; Saberi, R. S ; Sharif University of Technology
    The electrochemical behavior of catechol in the presence of propylthiouracil (PTU) and methylthiouracil (MTU) at a glassy carbon electrode is thoroughly investigated. The cyclic voltammetric studies of the systems are performed in different pHs and sweep rates. The results of the voltammetric foundations show an electrocatalytic oxidation of catechol in the presence of PTU and MTU, leading to a remarkable increase in the anodic peak current of catechol together with the contemporaneous disappearance of the corresponding cathodic wave. The presented mechanism shows the nucleophilic addition/reduction of the electro-generated o-quinone by the PTU or MTU, which produced chemically reduced... 

    Nucleophilic addition of thiaproline to electrochemically derived o-quinone, application to the sensitive voltammetric detection of thiaproline

    , Article Electroanalysis ; Volume 18, Issue 22 , 2006 , Pages 2225-2231 ; 10400397 (ISSN) Shahrokhian, S ; Amiri, M ; Sharif University of Technology
    The mechanism of electrochemical behavior of catechol in the presence of thiaproline is investigated by cyclic voltammetry, controlled-potential coulometry and spectrophotometric tracing of the reaction coordinate. The results indicate that thiaproline participate in with an ECEC mechanism in a nucleophilic (Michael) addition to o-quinone. Effect of pH of buffer solution on reaction pathway is studied and showed that addition of thiaproline to the o-quinone is performed only in solutions with pHs higher than 5. These results indicate that the addition of thiaproline is occurred first from amine functional group. In the second step, the addition of carboxylate group of thiaproline to C-5 of... 

    Fabrication and Investigation of Supercapacitors Based on Graphene Nanocomposites

    , Ph.D. Dissertation Sharif University of Technology Jokar, Effat (Author) ; Iraji Zad, Azam (Supervisor) ; Shahrokhian, Saeed (Supervisor)
    Development of renewable energy production from sun and wind and the development of hybrid electric vehicles seem to be integral components in modern societies in order to overcome the environmental pollution and reduce the use of fossil fuel sources. In such devices energy storage plays an important role and supercapacitor is one the important energy storage devices. Structure of supercapacitor electrodes has considerable effect on supercapacitor performance. Graphene as a 2D carbon structure can improve electrochemical properties of electrodes. Here three different hybrid structure of graphene have been realized. The high capacitance and cyclic stability of graphene nanosheets decorated... 

    Optical detection of phenolic compounds based on the surface plasmon resonance band of Au nanoparticles

    , Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 71, Issue 1 , 2008 , Pages 199-203 ; 13861425 (ISSN) Hormozi Nezhad, M. R ; Alimohammadi, M ; Tashkhourian, J ; Razavian, S. M ; Sharif University of Technology
    An indirect colorimetric method is presented for detection of trace amounts of hydroquinone (1), catechol (2) and pyrogallol (3). The reduction of AuCl4- to Gold nanoparticles (Au-NPs) by these phenolic compounds in the presence of cetyltrimethylammonium chloride (CTAC) produced very intense surface plasmon resonance peak of Au-NPs. The plasmon absorbance of Au-NPs allows the quantitative colorimetric detection of the phenolic compounds. The calibration curves derived from the changes in absorbance at λ = 568 nm were linear with concentration of hydroquinone, catechol and pyrogallol in the range of 7.0 × 10-7 to 1.0 × 10-4M, 6.0 × 10-6 to 2.0 × 10-4 M and 6.0 × 10-7 to 1.0 × 10-4 M,... 

    Photo-Fenton like degradation of catechol using persulfate activated by UV and ferrous ions: Influencing operational parameters and feasibility studies

    , Article Journal of Molecular Liquids ; Volume 249 , 2018 , Pages 463-469 ; 01677322 (ISSN) Delavaran Shiraz, A ; Takdastan, A ; Borghei, S. M ; Sharif University of Technology
    Elsevier B.V  2018
    In the present study, photo-Fenton degradation of catechol from aqueous solution was carried out using UV light and iron ions (Fe2+) as activators of persulfate (PS). Catechol degradation from solution was studied under different experimental variables such as solution pH (2.0–10.0), iron dosages (0.1–0.5 g/L), persulfate loadings (1.0–5.0 mM), initial catechol concentrations (20–100 mg/L) and scavengers (TBA and IPA). The comparative study of catechol removal showed that among the applied approaches, the order of degradation of catechol is as follows: PS/Fe2 +/UV > PS/Fe2 + > UV/PS > PS > UV. Furthermore, higher catechol degradation was observed with increasing iron dosage and PS... 

    Synthesis, characterization, electrochemical studies and catecholase-like activity of a series of mononuclear Cu(II), homodinuclear Cu(II)Cu(II) and heterodinuclear Cu(II)Ni(II) complexes of a phenol-based compartmental ligand

    , Article Journal of Molecular Catalysis A: Chemical ; Volume 241, Issue 1-2 , 2005 , Pages 1-7 ; 13811169 (ISSN) Boghaei, D. M ; Behzad, M ; Bezaatpour, A ; Sharif University of Technology
    A series of previously reported mononuclear Cu(II) and homodinuclear Cu(II)Cu(II) complexes, as well as, novel mononuclear Cu(II), homodinuclear Cu(II)Cu(II), and heterodinuclear Cu(II)Ni(II) complexes of a phenol-based dinucleating ligand with two different N(amine)2O2 and N(imine)2O2 coordination sites, were synthesized and characterized by elemental analyses, infrared and electronic absorption spectroscopies and conductivity measurements. The electrochemical behavior and catecholase-like activity of the complexes were also studied using cyclic voltammetry and UV-vis spectrophotometry, respectively. Our results show that the dinuclear complexes are more effective catalysts in the oxidation... 

    Electrochemical Determination of Piroxicam at thin Carbon
    Nanoparticle Composite And Investigation of the Electrochemical Behavior and Synthesis of Catechols in the Presence of Mercapto Methyl Tetrazol as a Nucleophile

    , M.Sc. Thesis Sharif University of Technology Jokar, Effat (Author) ; Shahrokhian, Saeed (Supervisor)
    The electrochemical oxidation behavior of the anti-inflammatory drug piroxicam was investigated. A carbon nanoparticle (CNP)-chitosan (CS) film-coated graphite electrode (PGE) was fabricated and the electrochemical behaviors of piroxicam on its surface was investigated by the means of cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). In comparison to the bare PGE, at the surface of the CNP-CS film modified electrode, the oxidation peak current of piroxicam increased significantly and the peak potential shifted negatively. Consequently, a simple and sensitive electroanalytical method was developed for the determination of piroxicam. The... 

    A novel enzyme based biosensor for catechol detection in water samples using artificial neural network

    , Article Biochemical Engineering Journal ; Volume 128 , 2017 , Pages 1-11 ; 1369703X (ISSN) Maleki, N ; Kashanian, S ; Maleki, E ; Nazari, M ; Sharif University of Technology
    Elsevier B.V  2017
    Biosensors could be used as digital devices to measure the sample infield. Consequently, computational programming along with experimental achievements are required. In this study, a novel biosensor/artificial neural network (ANN) integrated system was developed. Poly (3,4-ethylenedioxy-thiophene)(PEDOT), graphene oxide nano-sheets (GONs) and laccase (Lac) were used to construct a biosensor. The simple and one-pot process was accomplished by electropolymerizing 3,4-ethylenedioxy-thiophene (EDOT) along with GONs and Lac as dopants on glassy carbon electrode. Scanning electron microscopy (SEM) and electrochemical characterization were conducted to confirm successful enzyme entrapment. The... 

    Charge-transfer complexes of 4-nitrocatechol with some amino alcohols

    , Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 75, Issue 3 , 2010 , Pages 970-977 ; 13861425 (ISSN) Baniyaghoob, S ; Najafpour, M. M ; Boghaei, D. M ; Sharif University of Technology
    Charge-transfer (CT) complexes formed from the reactions of 4-nitropyrocatechol (4-nCat) as an electron acceptor with four amino alcohols: 2-aminoethanol, 1-amino-2-propanol, 4-aminobutanol and N-(2-hydroxyethyl)-1,3-diaminopropane (NHEDAP) as electron donors, have been studied spectrophotometrically in H2O and H2O/EtOH at 20, 25, 30, 35 and 40 °C. The calculated values of the oscillator strength and transition moment confirm the formation of CT-complexes. The thermodynamic and spectroscopic parameters were also evaluated for the formation of CT-complexes. The equilibrium constants ranged from 9.00 to 2.20 l mol-1 (M-1). These interactions are exothermic and have relatively large standard... 

    Power of a remote hydrogen bond donor: Anion recognition and structural consequences revealed by IR spectroscopy

    , Article Journal of Organic Chemistry ; Volume 80, Issue 2 , December , 2015 , Pages 1130-1135 ; 00223263 (ISSN) Samet, M ; Danesh Yazdi, M ; Fattahi, A ; Kass, S. R ; Sharif University of Technology
    American Chemical Society  2015
    Natural and synthetic anion receptors are extensively employed, but the structures of their bound complexes are difficult to determine in the liquid phase. Infrared spectroscopy is used in this work to characterize the solution structures of bound anion receptors for the first time, and surprisingly only two of three hydroxyl groups of the neutral aliphatic triols are found to directly interact with Cl-. The binding constants of these triols with zero to three CF3 groups were measured in a polar environment, and KCD3CN(Cl-) = 1.1 × 106 M-1 for the tris(trifluoromethyl) derivative. This is a remarkably large value, and high selectivity with respect to interfering anions such as, Br-, NO3 -... 

    Investigation of the electrochemical behavior of catechol and 4-methylcatechol in the presence of methyl mercapto thiadiazol as a nucleophile: application to electrochemical synthesis

    , Article Journal of Applied Electrochemistry ; Volume 40, Issue 1 , 2010 , Pages 115-122 ; 0021891X (ISSN) Shahrokhian, S ; Rastgar, S ; Sharif University of Technology
    The present study concerns the electrochemical behavior of catechol and 4-methylcatechol in the presence of 2-mercapto-5-methyl-1,3,4-thiadiazole (MMT) in aqueous medium on the surface of the glassy carbon electrode by means of cyclic voltammetry and controlled-potential coulometry. The oxidation mechanism was deduced from voltammetric and spectrophotometric data. The electro-generation of quinoid intermediates and their subsequent Michael-type reaction with MMT has been investigated as a clean and convenient strategy for the synthesis of corresponding reaction products. In addition, electro-synthesis of Michael addition products has been successfully accomplished by controlled-potential... 

    Efficient Fe/CuFeO2/rGO nanocomposite catalyst for electro-Fenton degradation of organic pollutant: Preparation, characterization and optimization

    , Article Applied Organometallic Chemistry ; Volume 33, Issue 10 , 2019 ; 02682605 (ISSN) Nazari, P ; Rahman Setayesh, S ; Sharif University of Technology
    John Wiley and Sons Ltd  2019
    The nanocomposite of zero-valent iron and delafossite CuFeO2 supported on reduced graphene oxide was synthesized for the first time to evaluate its performance as the heterogeneous catalyst toward electro-Fenton (EF) removal of catechol. X-ray diffraction, Fourier transform-infrared, scanning electron microscopy and Brunauer–Emmett–Teller (BET) were used to characterize the nanocomposite. It was found that the rhombohedral structure of CuFeO2 remained stable during the nanocomposite preparation. The BET surface area of the nanocomposite increased about 102 times in comparison with bare CuFeO2. The influence of the operating parameters was investigated. The optimum operating conditions were... 

    Mercaptotriazole as a nucleophile in addition to o-quinone electrochemically derived from catechol: Application to electrosynthesis of a new group of triazole compounds

    , Article Electrochemistry Communications ; Volume 7, Issue 1 , 2005 , Pages 68-73 ; 13882481 (ISSN) Shahrokhian, S ; Amiri, M ; Sharif University of Technology
    Electrochemical oxidation of catechol in the presence of 3-mercapto-1,2,4-triazole (MTA) as a nucleophile in aqueous buffered solutions was studied by cyclic voltammetry and controlled-potential coulometry. The mechanism of electrochemical reaction is confirmed by spectrophotometric tracing in various times of controlled-potential coulometry. The voltammetric and spectrophotometric foundations indicate that a 1,4 Michael addition of MTA from its thiol moiety to the electrochemically derived o-quinone is occurred. The electrochemical synthesis of Michael addition product has been successfully accomplished by controlled-potential coulometry in a divided H-type cell and the reaction product was... 

    Naphthalene metabolism in Nocardia otitidiscaviarum strain TSH1, a moderately thermophilic microorganism

    , Article Chemosphere ; Volume 72, Issue 6 , 2008 , Pages 905-909 ; 00456535 (ISSN) Zeinali, M ; Vossoughi, M ; Ardestani, S. K ; Sharif University of Technology
    The thermophilic bacterium Nocardia otitidiscaviarum strain TSH1, originally isolated in our laboratory from a petroindustrial wastewater contaminated soil in Iran, grows at 50 °C on a broad range of hydrocarbons. Transformation of naphthalene by strain TSH1 which is able to use this two ring-polycyclic aromatic hydrocarbon (PAH) as a sole source of carbon and energy was investigated. The metabolic pathway was elucidated by identifying metabolites, biotransformation studies and monitoring enzyme activities in cell-free extracts. The identification of metabolites suggests that strain TSH1 initiates its attack on naphthalene by dioxygenation at its C-1 and C-2 positions to give... 

    Degradation of phenanthrene and anthracene by Nocardia otitidiscaviarum strain TSH1, a moderately thermophilic bacterium

    , Article Journal of Applied Microbiology ; Volume 105, Issue 2 , 11 July , 2008 , Pages 398-406 ; 13645072 (ISSN) Zeinali, M ; Vossoughi, M ; Ardestani, S. K ; Sharif University of Technology
    Aims: The metabolism of phenanthrene and anthracene by a moderate thermophilic Nocardia otitidiscaviarum strain TSH1 was examined. Methods and Results: When strain TSH1 was grown in the presence of anthracene, four metabolites were identified as 1,2-dihydroxy-1,2-dihydroanthracene, 3-(2-carboxyvinyl)naphthalene-2-carboxylic acid, 2,3-dihydroxynaphthalene and benzoic acid using gas chromatography-mass spectrometry (GC-MS), reverse phase-high performance liquid chromatography (RP-HPLC) and thin-layer chromatography (TLC). Degradation studies with phenanthrene revealed 2,2′-diphenic acid, phthalic acid, 4-hydroxyphenylacetic acid, o-hydroxyphenylacetic acid, benzoic acid, a phenanthrene... 

    Delafossite-alumina nanocomposite for enhanced catalytic wet peroxide oxidation of anionic pollutants

    , Article Journal of Hazardous Materials ; Volume 417 , 2021 ; 03043894 (ISSN) Nazari, P ; Nouri, O ; Xie, Z ; Setayesh, S. R ; Wei, Z ; Sharif University of Technology
    Elsevier B.V  2021
    Mass transfer efficiency and catalytic reactivity are the two major hurdles for heterogeneous catalytic wet peroxide oxidation (CWPO) technologies. To address these issues, nanocomposite CuFeO2/Al2O3 was synthesized and assessed as a novel catalyst for enhanced adsorption and oxidation of anionic pollutants (catechol and reactive red 195 (RR195)) in waters. With a positive charge on the nanocomposite by introducing Al2O3, the adsorption of anionic pollutants was promoted. The surface complexation reaction on CuFeO2/Al2O3, which fits well to the Langmuir isotherm, has engined the mass transfer of pollutants to the nanocatalyst that demonstrated 96.46% and 99.75% removal of catechol and RR195...