39 research outputs found

    Pour une presse spécialisée en éducation au Sénégal

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    La presse sénégalaise est principalement une presse événementielle. Sur des sujets tels que l’économie ou l’éducation, rares sont les rédactions disposant de rubriques spécialisées, avec des journalistes ayant reçu une formation à leur métier. Des initiatives individuelles récentes tentent d’y remédier, dans un contexte de prise de conscience de l’importance des besoins éducatifs et de la nécessité d’impliquer toute la société dans ces questions qui concernent l’avenir du pays. L’auteur, président des Assises de l’éducation, dont la mission est de formuler des recommandations au gouvernement pour une refondation de l’école au Sénégal, considère que le rôle des médias est déterminant dans cet enjeu de société.The Senegalese press is mainly event-focused. In areas such as the economy or education, -publications producing columns written by journalists trained in their specialist field are few and far between. Recent individual initiatives have attempted to remedy this situation in a context of rising awareness about the importance of educational needs and the necessity of involving society as a whole in issues concerning the future of the country. The author, who presides the Assises de l’éducation – whose remit is to submit recommendations to the government regarding the overhaul of schools in Senegal – considers that the media has a decisive role to play vis-à-vis this societal issue.La prensa senegalesa es principalmente una prensa dedicada al tratamiento de los acontecimientos. Sobre unos temas como la economía o la educación, son muy pocas las redacciones que disponen de unas rúbricas especializadas, con unos periodistas que recibieron una formación para ejercer su oficio. Unas recientes tentativas individuales procuran remediar este problema, en un contexto de toma de conciencia de la importancia de las necesidades educativas y de la exigencia de implicar a toda la sociedad en estas cuestiones que conciernen el porvenir del país. El autor, presidente de los Encuentros de la educación (Assises de l’Éducation) cuya misión es entregar unas recomendaciones al gobierno para una refundación de la escuela en Senegal, considera que el papel de los medios de comunicación es determinante en este reto social

    COPPER(II) COMPLEXES OF o-VANILLIN ACETYLHYDRAZONE (H2L) AND THE SINGLE-CRYSTAL X-RAY STRUCTURE OF [{Cu(HL)(H

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    A hydrazonic ligand, o-vanillin acetylhydrazone (H2L) has been prepared and used as chelating agent towards copper(II) ion. The ligand acts like a tridentate ligand in the monodeprotonated (HL-) and dideprotonated (L2-) states. Monoanionic complexes [{Cu(HL)(H2O)}2]•2BF4 and [{Cu(HL)(Hpz)(H2O)}]•NO3 have been isolated. After neutralization the complex [{Cu(L)}2].5/2H2O is obtained. These complexes have been characterized by a range of physicochemical and spectroscopic studies. The X-ray crystal structure of the mononuclear complex [{Cu(HL)(Hpz)(H2O)}]•NO3 was also determined. This crystal is orthorombic with the space group I222, a = 13.417(3), b = 22.662(6), c = 22.518(5) Å, α = β = γ = 90° and Z = 8. The copper ion has a square-pyramidal geometry with the basal donors atoms from the tridentate ligand (ONO) and the pyrazole (N), the apical position being occupied by a coordinated water molecule weakly linked to the copper(II) center. The binuclear complexes exhibit interesting magnetic properties. KEY WORDS: Copper(II) complexes, Tridentate ligand, o-Vanillin acetylhydrazone, X-Ray crystal structure Bull. Chem. Soc. Ethiop. 2006, 20(1), 35-43

    Chlorido[N′-(2-oxidobenzil­idene)acetohydrazide-κ2 O,N′,O′]copper(II) dihydrate

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    In the title complex, [Cu(C9H9N2O2)Cl]·2H2O, prepared from the Schiff base ligand N′-(2-hydroxy­benzil­idene)aceto­hydrazide and copper(II) chloride, the CuII atom is coord­inated by two O atoms and one N atom from the ligand and by a Cl atom in a distorted square-planar geometry. The two donor O atoms of the tridentate Schiff base ligand are in a trans arrangement. In the crystal structure, there is an extensive inter­molecular hydrogen-bonding network; N—H⋯O, O—H⋯O and O—H⋯Cl inter­actions, involving the uncoordinated water mol­ecules, lead to the formation of a two-dimensional network parallel to the ab plane

    Bis(2-benzamido­benzimidazolato-κ2 N 1,O)(N,N-dimethyl­formamide-κO)copper(II)

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    In the title compound, [Cu(C14H10N3O)2(C3H7NO)], the CuII atom is five-coordinated by two N,O-bidentate 2-benzamido­benzimidazolate anions and one O-coordinated dimethyl­formamide (DMF) mol­ecule, resulting in a distorted square-based pyramidal CuN2O3 geometry for the metal atom, with the DMF O atom at the apical site. In the crystal structure, inter­molecular N—H⋯N hydrogen bonds result in chains of mol­ecules propagating along [100]

    Bis(imidazole-κN 3)bis­(nitrato-κO)zinc(II)

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    The title complex, [Zn(NO3)2(C3H4N2)2], contains a ZnII centre with a slightly distorted tetra­hedral coordination environment, involving two N atoms from imidazole ligands and two O atoms from nitrate anions. The imino NH groups participate in inter­molecular N—H⋯O hydrogen bonds

    1,2-Bis(N′-benzoyl­thio­ureido)benzene

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    The title compound, C22H18N4O2S2, was characterized by 1H and 13C NMR, solid-state IR spectroscopy and X-ray crystallographic techniques. The crystal structure determination reveals that the twisting modes of the two side arms are different [C—N—C—O and C—N—C—N torsion angles = −1.2 (3) and 1.1 (3)°, respectively, in one arm and 24.1 (3) and −5.1 (3)°, respectively, in the other]. The crystal structure involves N—H⋯O and N—H⋯S hydrogen bonds

    4,6-Dimethyl-2-thioxo-1,2-dihydro­pyrimidin-3-ium chloride–thio­urea (1/1)

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    In the title compound, C6H9N2S+·Cl−·CH4N2S, the 4,6-di­methyl-2-thioxo-1,2-dihydro­pyrimidin-3-ium cation is proton­ated at one of the pyrimidine N atoms. The cations are bridged by the chloride anions through a pair of N—H⋯Cl hydrogen bonds. The amino groups of each thio­urea adduct inter­act with the chloride anions through a pair of N—H⋯Cl hydrogen bonds and the S atom of another thio­urea adduct through a pair of N—H⋯S hydrogen bonds. These inter­actions result in a layered hydrogen-bonded network propagating parallel to the bc plane. Except for two H atoms, all atoms are on special positions

    Poly[di-μ-aqua-diaqua-di-μ6-malonato-cobalt(II)dipotassium(I)]

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    In the title complex, [CoK2(C3H2O4)2(H2O)4]n, the Co atom is located on a position with site symmetry 2/m, the K atom and one water mol­ecule are located on a mirror plane, and the malonate and one water mol­ecule are located on a twofold rotation axis. The KI atom is seven-coordinated by four carboxyl­ate O atoms from four malonate ligands and by three water O atoms, forming a distorted polyhedron. The CoII atom is in an almost octa­hedral environment formed by four carboxyl­ate O atoms from two malonate ligands and two water O atoms. The structure consists of layers parallel to (20) built up from edge-sharing KO7 and CoO6 polyhedra, which are connected by O—H⋯O hydrogen bonding including water mol­ecules into a three-dimensional network

    Synthesis, physical studies and crystal structure determination of Y(III) and Er(III) complexes of 1-(pyridin-2-yl)-2-(pyridine-2-ylmethylene)hydrazine

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    Two isotype mononuclear yttrium(III) and erbium(III) complexes, {[Y(HL)(OAc)2(H2O)2]. (H2O)∙(NO3)} (1) and {[Er(HL) (OAc)2(H2O)2].(H2O)∙(NO3)} (2), where HL is the neutral Schiff base ligand 1-(pyridin-2-yl)-2-(pyridine-2-ylmethylene)hydrazine, and OAc is the acetate anion, have been synthesized and characterized by physicochemical methods and single crystal X-ray determination. Both complexes crystallizes in the triclinic space group Pī with unit cell dimensions for complex of Y(III) a = 7.909 (2) Å, b = 11.718 (4) Å, c = 12.497 (3) Å,    α = 78.907 (3)°, b = 73.840 (3)°, γ = 72.074 (3)°, V = 1051.26 (6) Å3, Z = 2, R1 = 0.051 and    wR2 = 0.112 and for complex of Er(III)a = 7.913 (1) Å, b = 11.719 (2) Å, c = 12.487 (2) Å,          α = 78.832 (1)°, α = 73.674 (1)°, γ = 72.012 (1)°, V = 1049.64 (3) Å3, Z = 2, R1 = 0.028, and   wR2 = 0.062. In both complexes, the coordination polyhedra around Ln(III) atoms are best described as a distorted tricapped trigonal prism. Antioxidant activities of the ligand and its Y(III) and Er(III) complexes are studied
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