Ali Ourari

Université de Rennes 1, Roazhon, Brittany, France

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Publications (50)86.33 Total impact

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    ABSTRACT: We describe the synthesis and characterization of a new tetradentate Schiff base ligand obtained from 2,3-diaminopyridine and 5-methoxysalicylaldehyde. This ligand (H2L) reacted with nickel(II), copper(II), and zinc(II) acetates to give complexes. The ligand and its metal complexes were characterized using analytical, spectral data (UV-vis, IR, and mass spectroscopy), and cyclic voltammetry (CV). The crystal structure of the copper complex was elucidated by X-ray diffraction studies. The electrochemical behavior of these compounds, using CV, revealed that metal centers were distinguished by their intrinsic redox systems, e.g. Ni(II)/Ni(I), Cu(II)/Cu(I), and Zn(II)/Zn(I). Moreover, the electrocatalytic reactions of Ni(II) and Cu(II) complexes catalyze the oxidation of methanol and benzylic alcohol.
    No preview · Article · Dec 2015 · Journal of Coordination Chemistry
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    ABSTRACT: Solid like carbon paste electrodes (SCPEs) are built using different carbon materials namely carbon black N110, N220, N375, N772 and acetylene black. The electrochemical behavior of these electrodes and the influence of carbon black/paraffin ratio were studied and the results were discussed and compared to other electrodes prepared with graphite, mesoporous carbon and nanopowder carbon. Cyclic voltammetry, amperometry and electrochemical impedance spectroscopy were employed for their electrochemical and analytical characterizations. Amperometric measurements using N110, N220, N375 SCPEs with solid paraffin, showed a linear response of benzoquinone concentration with a detection limit of 75, 32 and 171nM respectively.
    Full-text · Article · Dec 2015 · Electroanalysis
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    ABSTRACT: Carbon black is selected as electrode materials, to elucidate the effects of particle size and surface area compared with other carbon materials on the electrochemical properties of different fabricated electrodes, cyclic voltammetry and electrochemical impedance spectroscopy are used for electrochemical characterization of carbon black nanoparticles (CBNPs) which produce a number of effective electrochemical probes for the sensitive detection of many different species. Different carbon black nanoparticles namely carbon black N110, N220, N375, N772 and acetylene black are selected as electrode materials for carbon paste electrode development using both solid and liquid paraffin as binder. The electrochemical behavior of the carbon black electrodes and the influence of carbon black/paraffin ratio were studied, and the results were discussed and compared to other electrodes prepared with graphite, mesoporous carbon and nanopowder carbon. Cyclic voltammetry and electrochemical impedance spectroscopy are employed for electrochemical characterization. The electroanalytical performances of different electrodestoward nitrites and benzoquinone (BQ) were evaluated with cyclic voltammetry, differential pulse voltammetry and amperometry. The amperometric measurements using N110, N220, N375 carbon black paste electrodes with solid paraffin as binder, showed a linear response of benzoquinone concentration with a detection limit of 75, 32 and 171 nM, respectively. The carbon paste electrode prepared by using the nanomaterial carbon black and solid paraffin offers great promise for creating a new class of carbon paste electrodes employing low cost nanomaterial for sensing applications.
    Full-text · Conference Paper · Nov 2015
  • Ali Ourari · Djouhra Aggoun
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    ABSTRACT: Three dihydroxylated acetophenone derivatives 2,6-(1a), 2,5-(2a), and 2,4-dihydroxyacetophenone (3a) were O-monoalkylated at moderate temperature (50 °C) using 3-bromopropyl-N-pyrrole. These monomers 6-(3′-N-pyrrolpropoxy)-2-hydroxyacetophenone (1b), 5-(3′-N-pyrrolpropoxy)-2-hydroxyacetophenone (2b), and 4-(3′-N-pyrrolpropoxy)-2-hydroxy acetophenone (3b) were isolated with acceptable yields (59–70 %). Their characterization was carried out with usual spectroscopic methods such as UV–vis, FTIR, NMR1H, 13C, Dept135, and elemental analysis. These pyrrolic compounds were deliberately chosen as electropolymerizable monomers to elaborate poly(pyrrole) films containing metallic centers useful as redox mediators covalently grafted on the surfaces of modified electrodes. Accordingly, we have initiated the synthesis of an original pyrrole-Ni(II)-Schiff base complex derived from 2,6-(1b) and 1,2-diaminoethane. This pyrrolic complex was electropolymerized onto glassy carbon (GC), platinum disk (Pt), and indium tin oxide (ITO) electrode surfaces. This electropolymerization was performed in acetonitrile via anodic oxidation of pyrrolic moieties by cyclic voltammetry. The efficiency of the electrochemical polymerization was investigated as a function of several parameters such as the nature of the electrode material, the number of voltammetric scans, and the scan rate dependence. The electrodeposited poly(pyrrole) films onto ITO surface was characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). This poly(pyrrole) matrix, containing metallic centers, was found to have good catalytic properties towards the reduction of iodobenzene and carbon dioxide CO2. Graphical abstract
    No preview · Article · Nov 2015 · Journal of the Iranian Chemical Society
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    ABSTRACT: An unsymmetrical bidentate Schiff base ligand, ethane 2-(4-methox-yphenyl)-1-iminosalicylidene, and its novel two mononuclear complexes, Nickel(II) [Ni(II)-2L] and Manganese(III) [Mn(III)Cl-2L] where L represents the ligand, have been synthesized and characterized by various physicochemical methods. The Ni(II) ion is coordinated by two nitrogen and two oxygen atoms with both the bidentate Schiff base ligands in an approximately square planar coordination geometry, while the manganese complex, the Mn(III) ion, is involved in an additional contact with one chloride anion for which the coordination sphere appears as a square pyramidal arrangement. The thermogravimetric analyses of the synthesized compounds revealed three different stages of decomposition for NONO bis-biden-tate manganese and nickel complexes. The cyclic voltammetry studies of these complexes in N,N-dimethylformamide showed a redox couple for each one of them, such as Ni(II)/Ni(I) and Mn(III)/Mn(II), which are quasi-reversible. Their catalytic behaviors were tested showing that the nickel complex is an effective electrocatalyst in the reduction of bromocyclopentane. Regarding the manganese complex, it was revealed that it is an efficient catalyst in the activation of molecular dioxygen, & Brahim Bouzerafa
    Full-text · Article · Oct 2015 · Research on Chemical Intermediates
  • Ali OURARI · Wassila DERAFA · Djouhra AGGOUN
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    ABSTRACT: This work describes the synthesis of a new unsymmetrical tetradentate copper(ii) Schiff base complex Cu(L)(Py)(ClO4) containing N3O donor atoms. The tridentate ligand (HL) has been prepared by condensation of dehydroacetic acid on 1,2-diaminopropane in methanol. The reaction of the ligand with an appropriate amount of copper(ii) perchlorate hexahydrate (1 : 1 ratio) in the same solvent and in the presence of an excess of pyridine (Py) yields the title compound. The tridentate ligand (HL) with pyridine act as mixed ligands where three nitrogen and an enolic oxygen atoms were chelated to the copper centre. This complex has been fully characterized by FT-IR, UV-Vis spectrophotometry, and cyclic voltammetry. Single crystal X-ray diffraction of this complex showed that the copper ion was coordinated by one ligand, one pyridine molecule with one perchlorate anion in a square pyramidal geometry. The Cu(L)(Py)(ClO4) complex crystallizes in an orthorhombic system, space group of P¯cab with a = 11.051, b = 15.58, c = 21.736 Å and Z = 8. The electrochemical reduction of the copper(ii) complex, in N,N-dimethylformamide (DMF) solvent using cyclic voltammetry, produces conducting polymeric films on different electrode substrates, such as glassy carbon (GC), indium tin oxide (ITO) and fluorine tin oxide (FTO). The catalytic activity of this complex in homogeneous and heterogeneous electrocatalytic media seems to be efficient for the electroreduction of bromocyclopentane and iodobenzene. This journal is
    No preview · Article · Sep 2015 · RSC Advances
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    ABSTRACT: Polystyrene functionalized by a Schiff base ligand as N,N’-bis(salicylidenepropylene triamine)-N-para-aminomethylpolystyrene was synthesized from poly(4-chloromethylstyrene) and Schiff base ligand N,N’-bisalicylidenepropylenetriamine. Coordinatated with nickel ion, this polystyrene Schiff base gives the expected nickel complex. The modified electrodes obtained from graphite paste and nickel complex covalently grafted onto the polystyrene were prepared in a ratio 70:30 wt%. Its voltammogram, recorded in alkaline solution, showed a well- defined redox process corresponding to Ni(II)/Ni(III) redox couple. This modified graphite paste electrode showed a good stability. The electrocatalytic activity of the oxidation reaction of some aliphatic alcohols has been studied by cyclic voltammetry with various concentrations and different scan rates. Thus, these electrodes revealed good electrocatalytic activity towards methanol, ethanol and isopropanol alcohols showing that the oxidation current peak increases linearly with alcohol concentration. However, the electrocatalytic current decreases with the increase of the length of the aliphatic chain as expressed by the following sequence: icata (methanol) > icata (ethanol) > icata (isopropanol).
    No preview · Article · May 2015 · Electrochimica Acta
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    ABSTRACT: A new tetradentate cobalt(II)-Schiff base complex has been synthesized via the reaction of the ligand 2,2’-((1E,1’E)-(ethane-1,2-diylbis(azanylylidene))bis(ethan-1-yl-1-ylidene))bis(4-((methyl(phenyl)amino)methyl)phenol) with a stoichiometric amount of cobalt(II) acetate tetrahydrate in absolute ethanol. This cobalt(II) complex has been characterized with the aid of several spectroscopic techniques (FT-IR, UV-Vis, and mass spectrometry) as well as by thermal (TGA and DTA) and elemental analysis. Cyclic voltammetry has been employed to examine the redox behavior of the cobalt(II) complex in dimethylformamide (DMF) containing 0.10 M tetra-n-butylammonium tetrafluoroborate (TBABF4). In addition, the electrogenerated cobalt(I) form of the complex has been (a) employed as a catalyst for the reduction of 1-iododecane and (b) compared with the behavior of cobalt(I) salen. Finally, the cobalt(II) complex has been subjected to anodic electropolymerization onto the surface of a glassy carbon electrode in DMF containing 0.10 M tetra-n-butylammonium perchlorate (TBAP).
    No preview · Article · May 2015 · Polyhedron
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    ABSTRACT: Anion radicals of a series of aromatic compounds (C6H5CN, C6H5COOEt, anthracene, 9,10-dimethyl-, 9,10-diphenyl- and 9-phenylanthracene, pyrene and naphthalene) react with trialkyl chlorosilanes R1R2R3SiCl (R1−3 = Me, Et; R1,2 = Me, R3 = t-Bu) in multiple ways, following classical bimolecular schemes. The ratio of one-electron transfer (ET) to a two-electron process (SN2-like nucleophilic attack of the reduced form of mediator on the chlorosilane, with k2 ≅ 102-108 M−1 s−1) is inversely related to the steric availability of Si for nucleophilic displacement reactions. The nucleophilic substitution pathway mainly results in mono- and disilylated aromatic products. Paralleling the electrochemical data with DFT calculations, the role of silicophilic solvent (DMF) in SN process was shown to be quite complex because of its involvement into coordination extension at silicon, dynamically modifying energetics of the process along the reaction coordinate. Although 2,2'-bipyridine also forms delocalized persistent anion radicals, they do not induce neither ET nor SN reactions in the same manner as aromatic mediators. Silicophilicity of 2,2'-bipyridine being superior to that of DMF, a R3SiCl•bipy complex of hypercoordinated silicon with electroactive ligand was formed instead, whose reduction requires about 1 V less negative potentials than bipyridine itself.
    Full-text · Article · Mar 2015 · Electrochimica Acta
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    ABSTRACT: In the title compound, [Cu(C 10 H 11 BrNO) 2 ], the asymmetric unit consists of one-half of the molecule, the other half being generated by an inversion centre. Hence the Cu II cation is symmetrically coordinated by two bidentate Schiff base anions in a slightly distorted square-planar environment with Cu—O and Cu—N bond lengths of 1.8786 (19) and 2.009 (2) Å, respectively. In the crystal, individual molecules are packed in alternating zigzag layers parallel to (001). Weak C—H...π interactions exist between the molecules.
    Full-text · Article · Feb 2015
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    Ali Ourari · Bouzid Ketfi · Larbi Zerroual
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    ABSTRACT: Nickel (II)-DHS Complex was obtained from N,N’-bis(2,5-dihydroxybenzylidene)-1,2-diaminoethane (H2DHS) ligand and nickel acetate tetrahydrated in ethanolic solution with stirring under reflux. This complex, dissolved in an alkaline solution, was oxidized to form electroactive films strongly adhered on the ITO (Indium tin oxide) electrode surface. In this alkaline solution, the poly-[NiII-DHS]/ITO films showed the typical voltammetric response of (Ni2+/Ni3+) redox couple centers which are immobilized in the polymer-film. The modified electrodes (MEs) obtained were also characterized by several techniques such as scanning electronic microscopy, atomic force microscopy and electrochemical methods. The electrocatalytic behavior of these MEs towards the oxidation reaction of some aliphatic alcohols such as methanol, ethanol, 2-Methyl-1-propanol and isopropanol was investigated. The voltammograms recorded with these alcohols showed a good electrocatalytic efficiency. The electrocatalytic currents were at least 80 times higher than those obtained for the oxidation of methanol on electrodes modified with nickel hydroxide films in alkaline solutions. We noticed that these electrocatalytic currents are proportional to the concentration of methanol (0.050 to 0.30 μM). In contrast, those recorded for the oxidation of other aliphatic short chain alcohols such as ethanol, 2-Methyl-1-propanol and isopropanol are rather moderately weaker. In all cases the electrocatalytic currents presented a linear dependence with the concentration of alcohol. These modified electrodes could be applied as alcohol sensors.
    Preview · Article · Nov 2014 · Arabian Journal of Chemistry
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    ABSTRACT: The removal of cetylpyridinium bromide (CPB) from aqueous solutions was investigated using a mineral adsorbent called Maghnite (a bentonite obtained from Maghnia, West Algeria). The adsorption kinetics of CPB on Maghnite is pseudo-second order and the adsorption isotherm follows essentially the model of Redlich–Peterson. The results obtained show that CPB is adsorbed on Maghnite with an adsorption capacity of 0.438 mmol/g (168.4 mg/g). Physical data indicate that CPB is efficient for the deinking of newspaper solutions, only when the natural Maghnite is associated to CPB. These results are of practical interest, since CPB shows a double action—to protect and to optimize aquatic environment.
    No preview · Article · Jul 2014 · Journal of Surfactants and Detergents
  • Ali Ourari · Djouhra Aggoun · Lahcène Ouahab
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    ABSTRACT: Three monomers 6-[3'-N-pyrrolpropoxy]-2-hydroxyacetophenone (1), 5-(3'-N-pyrrol propoxy)-2-hydroxyacetophenone (2) and 4-(3'-N-pyrrolpropoxy)-2-hydroxyacetophenone (3) were synthesized and their poly(pyrrole) films were electrodeposited on glassy carbon (GC) and Indium tin oxide (ITO) conductive electrodes by anodic oxidation in acetonitrile solutions containing n-Bu)(4)N+CIO4- (TBAP 0.1 M). These films, currently called modified electrodes (noted ME), were obtained by the successive cycling at the appropriate potentials. These films contain chelating sites such as carbonyl group bearing the phenolic function which could play an important role in coordination chemistry. The electrodeposited poly(pyrrole) films on the ITO conductive glass electrodes offer some analytical advantages as the optical and electronic properties. Consequently, these new materials of electrodes were characterized by cyclic voltammetry while the morphology of these films was studied by FT-IR spectroscopy, scanning electron microscopy (SEM), dispersive energy X-ray spectroscopy and atomic force microscopy (AFM). The AFM studies show that the morphology of polypyrrole (PPy) films, electrodeposited on ITO surface, depends on the specific structure of the compound deriving from the monoalkylated dihydroxyacetophenone 1.2 and 3. The coordination of copper was performed by electroreduction reaction in presence of ligand (3) and copper acetate salt. The resulting electrode material was tested towards the electrocatalytic activity in the reduction of bromocyclopentane.
    No preview · Article · Apr 2014 · Colloids and Surfaces A Physicochemical and Engineering Aspects
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    ABSTRACT: The title Schiff base, C 17 H 13 NO 2 , crystallizes in the zwitterionic form and an N—H...O hydrogen bond closes an S (6) ring. The dihedral angle between the aromatic ring systems is 15.62 (9)°. In the crystal, O—H...O hydrogen bonds link the molecules into C (11) chains propagating in [010].
    Preview · Article · Feb 2014 · Acta Crystallographica Section E Structure Reports Online
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    ABSTRACT: A tetradentate Schiff base ligand (3) has been synthesized via the reaction of 5′-(N-methyl-N-phenylaminomethyl)-2′-hydroxyacetophenone (2) with a stoichiometric amount of ethylenediamine in absolute ethanol. Compound 2 was prepared by reaction of 5′-chloromethyl-2′-hydroxyacetophenone (1) with N-methylaniline, in the presence of sodium bicarbonate in tetrahydrofuran. Compound 1, on the other hand, was obtained through a reaction between a hydrochloric acid–formaldehyde mixture and 2′-hydroxyacetophenone. Refluxing a mixture of the Schiff base (3) and a stoichiometric amount of nickel(II) acetate tetrahydrate in absolute ethanol at 50 °C under a nitrogen atmosphere afforded the expected tetradentate nickel(II)-Schiff base coordination compound (4). Compounds 1–4 have been characterized with the aid of a number of techniques: UV–Vis spectrophotometry; FT-IR, 1H NMR, 13C NMR, and mass spectrometry; and elemental analysis. Cyclic voltammetry has been employed to investigate the redox behavior of compound 4 as well as the ability of the electrogenerated nickel(I) form of 4 to catalyze the reduction of 1-iodooctane.
    Full-text · Article · Jan 2014 · Polyhedron
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    ABSTRACT: A pentadentate Schiff base, 2,2 '-(((azanediylbis(propane-3,1-diyl))bis(azanylylidene))bis(methanylylidene))diphenol (1), has been synthesized via the reaction of salicylaldehyde with N-1-(3-aminopropyl)propane-1,3-diamine [HN(C3H6NH2)(2)] in absolute ethanol. Refluxing a mixture of 1 with the hydrated acetate salts of nickel(II), zinc(II), iron(II), and copper(II) affords each of the expected M(II)-Schiff base complexes. These complexes have been characterized by means of FT-IR, H-1 NMR, C-13 NMR, and mass spectrometry as well as UV-Vis spectrophotometry and elemental analysis. In addition, the molecular structures of the copper(II) and nickel(II) complexes were determined by means of X-ray crystallography. Antioxidant and antibacterial activities of 1 and its complexes were evaluated in vitro. Highest DPPH radical-scavenging activity was observed for Fe(ll)-1 with an IC50 of 0.39 mg mL-1, followed by 1 (IC50 = 3,38 +/- 0.01 mg mL(-1)). Use of the beta-carotene-linoleic acid bleaching assay revealed that 1 has the highest antioxidant activity and has significant inhibition of lipid peroxidation with 1% of 94.21 +/- 0.003%, followed by Fe(ll)-1 and Ni(II)-1 with I% of 34.29 +/- 2.08% and 30.77 +/- 1.91%, respectively. Antibacterial activity of 1 and its transition-metal complexes was investigated by use of disk diffusion assay; Zn(II)-1 and Ni(II)-1 exert a high inhibition of the growth of all bacterial strains with inhibition diameters ranging from 8 to 14 mm.
    Full-text · Article · Jan 2014 · Polyhedron
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    ABSTRACT: In the title hydrate, C17H18N2O5·H2O, the complete organic mol-ecule is generated by a crystallographic mirror plane with one C and one O atom lying on the mirror plane. The O atom of the water mol-ecule has m site symmetry. Two symmetry-related intra-molecular O-H⋯O hydrogen bonds complete S(6) rings in the organic mol-ecule. In the crystal, the components are linked into (010) sheets by O-H⋯O and N-H⋯O hydrogen bonds.
    Full-text · Article · Oct 2013 · Acta Crystallographica Section E Structure Reports Online
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    ABSTRACT: Both screen‐printed electrodes modified with a dispersion of carbon black (CB) and solid paste electrodes prepared using a nanostructured CB were developed and characterized. Indeed, increasing the peak currents and/or their shifting to negative potentials were observed, exhibiting efficient electrocatalytic activity towards nitrite oxidation with high sensitivity and low detection limit. Solid carbon paste electrodes (SCPEs) and solid carbon black paste electrodes (SCBPEs) were challenged in amperometric mode with nitrite since detection limit reached is 65 and 5 nM respectively. Nitrate was first reduced to nitrite in reductor column, then detected on SCBPEs. Nitrate and nitrite were determined in real samples.
    No preview · Article · Sep 2013 · Electroanalysis
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    Ali Ourari · Djouhra Aggoun · Lahcene Ouahab
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    ABSTRACT: A new copper(II) complex Cu(II)-L containing N2O2 donor atoms has been prepared from 6-[3'-(N-pyrrol) propoxy]-2-hydroxyacetophenone and diaminoethane in the presence of copper acetate monohydrate. It was characterized by spectroscopic methods such as FT-IR, UV-vis, mass spectra, elemental analysis and cyclic voltammetry. The molecular structure of Cu(II)-L has also been confirmed by X-ray diffraction analysis. The electrochemical behavior of copper(II)-Schiff base complex containing pyrrol groups has been investigated in DMF and acetonitrile solutions using cyclic voltammetry. Thus, conducting polymeric films of polypyrrole were obtained on the surfaces of glassy carbon and ITO electrodes using copper(II) complex as monomer. The modified electrodes were electrochemically and morphologically characterized and their electrocatalytic properties in heterogeneous phase have also been investigated. The AFM studies show that the morphology of polypyrrole (PPy) films on ITO-electrodes depends on the number of cyclical scans. The electrocatalytic performances of this complex seem to be more efficient towards the electro-oxidation of isopropylic alcohol than any other kinds of alcohols such as methanol, ethanol and benzyl alcohol. The electro-reduction of carbon dioxide was also examined. (c) 2013 Elsevier B.V. All rights reserved.
    Preview · Article · Jul 2013 · Inorganic Chemistry Communications
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    ABSTRACT: In the title 1:1 adduct, C9H12N2O2·C6H6O, the dihedral angle between the benzene ring and the salicylic amide group is 6.68 (6)°. The conformation of the amide group is supported by two intra-molecular N-H⋯O hydrogen bonds, which close S(6) and S(7) rings. In the crystal, the components are linked by O-H⋯O and N-H⋯O hydrogen bonds, generating (100) sheets.
    Full-text · Article · Apr 2013 · Acta Crystallographica Section E Structure Reports Online

Publication Stats

212 Citations
86.33 Total Impact Points

Institutions

  • 2015
    • Université de Rennes 1
      Roazhon, Brittany, France
  • 1992-2015
    • Ferhat Abbas University of Setif
      • Department of Processes Engineering
      Satif, Sétif, Algeria
  • 1995-1997
    • University Joseph Fourier - Grenoble 1
      • Département de chimie moléculaire
      Grenoble, Rhône-Alpes, France