Libasse Diop

Cheikh Anta Diop University, Dakar, Dakar, Dakar, Senegal

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Publications (136)38.91 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The crystal structure of the hydrated title salt, 2C 6 H 13 N 2 + ·S 2 O 3 2− ·2H 2 O, contains a centrosymmetric cyclic motif of eight hydrogen-bonded molecular subunits. Two DABCOH + cations (DABCO = 1,4-diazabicyclo[2.2.2]octane) are linked to two water molecules and two thiosulfate anions via O—H...N and O—H...O hydrogen bonds, respectively. Two other water molecules close the cyclic motif through O—H...O contacts to the first two water molecules and to the two thiosulfate anions. A second pair of DABCOH + cations is N—H...O hydrogen bonded to the two anions and is pendant to the ring. Adjacent cyclic motifs are bridged into a block-like arrangement extending along [100] through O—H...O interactions involving the second pair of water molecules and neighbouring thiosulfate anions.
    No preview · Article · Mar 2016
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    ABSTRACT: In the structure of the title salt, {(C 5 H 14 N 3 )[CdCl 3 ]} n , the Cd II atom of the complex anion is five-coordinated by one terminal and four bridging Cl atoms. The corresponding coordination polyhedron is a distorted trigonal bipyramid, with Cd—Cl distances in the range 2.4829 (4)–2.6402 (4) Å. The bipyramids are condensed into a polyanionic zigzag chain extending parallel to [101]. The tetramethylguanidinium cations are situated between the polyanionic chains and are linked to them through N—H...Cl hydrogen bonds, forming a layered network parallel to (010).
    No preview · Article · Jan 2016
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    ABSTRACT: The structure of the mononuclear title complex, [{(H 3 CS) 2 C=NC[triple-bond] N} 2 CoCl 2 ], consists of a Co II atom coordinated in a distorted tetrahedral manner by two Cl − ligands and the terminal N atoms of two dimethyl N -cyanodithioiminocarbonate ligands. The two organic ligands are almost coplanar, with a dihedral angle of 5.99 (6)° between their least-squares planes. The crystal packing features pairs of inversion-related complexes that are held together through C—H...Cl and C—H...S interactions and π–π stacking [centroid-to-centroid distance = 3.515 (su?) Å]. Additional C—H...Cl and C—H...S interactions, as well as Cl...S contacts < 3.6 Å, consolidate the crystal packing.
    Preview · Article · Jan 2016
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    ABSTRACT: The complex title salt, (C 21 H 20 OP) 2 [CoCl 4 ], is the reaction product of CoCl 2 with acetonyltriphenylphosphonium chloride in acetonitrile. In the anion, the Co II atom exhibits a typical tetrahedral environment, with Co—Cl distances ranging from 2.2721 (6) to 2.2901 (6) Å, and with Cl—Co—Cl angles ranging from 106.12 (2) to 112.24 (2)°. The two phosphonium cations likewise show the expected tetrahedral configuration, with P—C distances ranging from 1.785 (2) to 1.8059 (18) Å and C—P—C angles ranging from 106.98 (8) to 112.85 (15)°. The molecules interact in the lattice mainly through Coulombic and van der Waals forces because there is no particular polarity to the charges carried by the cations or anion. In the crystal, the cations and anions are arranged in sheets parallel to (001).
    No preview · Article · Dec 2015
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    ABSTRACT: The asymmetric unit of the title compound, (C4H7N2)2[CoCl4], consists of two 2-methyl-imidazolium cations and one tetra-hedral [CoCl4](2-) anion. The anions and cations inter-act through N-H⋯Cl hydrogen bonds to define layers with a stacking direction along [100]. Besides van der Waals forces, weak C-H⋯Cl inter-actions between these layers stabilize the crystal packing.
    Preview · Article · Sep 2015
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    ABSTRACT: The crystal structure of the title salt adduct, 2C6H14N+·C4H4O4 2−·C4H6O4, consists of two cyclo­hexyl­ammonium cations, one succcinate dianion and one neutral succinic acid mol­ecule. Succinate dianions and succinic acid mol­ecules are self-assembled head-to-tail through O—H⋯O hydrogen bonds and adopt a syn–syn configuration, leading to a strand-like arrangement along [101]. The cyclo­hexyl­ammonium cations have a chair conformation and act as multidentate hydrogen-bond donors linking adjacent strands through inter­molecular N—H⋯O inter­actions to both the succinate and the succinic acid components. This results in two-dimensional supra­molecular layered structures lying parallel to (010).
    Full-text · Article · Aug 2015
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    ABSTRACT: The crystal structure of the title salt, [Fe(C 5 H 5 )(C 8 H 13 N)](HC 2 O 4 ), consists of discrete (ferrocenylmethyl)dimethylammonium cations and hydrogen oxalate anions. The anions are connected through a strong O—H...O hydrogen bond, forming linear chains running parallel to [100]. The cations are linked to the anions through bifurcated N—H...(O,O′) hydrogen bonds. Weak C—H...π interactions between neighbouring ferrocenyl moieties are also observed.
    Preview · Article · Aug 2015
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    ABSTRACT: The tin(IV) atom in the complex anion of the title salt, (C4H7N2)[Sn(C2O4)Cl3(H2O)], is in a distorted octa­hedral coordination environment defined by three chlorido ligands, an oxygen atom from a water mol­ecule and two oxygen atoms from a chelating oxalate anion. The organic cation is linked through a bifurcated N-HO hydrogen bond to the free oxygen atoms of the oxalate ligand of the complex [Sn(H2O)Cl3(C2O4)]- anion. Neighbouring stannate(IV) anions are linked through O-HO hydrogen bonds involving the water mol­ecule and the two non-coordinating oxalate oxygen atoms. In combination with additional N-HCl hydrogen bonds between cations and anions, a three-dimensional network is spanned.
    Full-text · Article · May 2015
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    ABSTRACT: Reaction of oxalic acid and di-phenyl-tin dichloride in the presence of cyclo-hexyl-amine led to the formation of the title salt, (C6H14N)2[Sn(C6H5)2(C2O4)2]. The dianion is made up from an Sn(C6H5)2 moiety cis-coordinated by two chelating oxalate anions, leading to an overall distorted octa-hedral coordination geometry of the Sn(IV) atom. The negative charges are compensated by two surrounding cyclo-hexyl-ammonium cations adopting chair conformations each. In the crystal, anions and cations are linked via a network of N-H⋯O hydrogen bonds into a layered arrangement parallel to (101).
    Full-text · Article · Feb 2015
  • S. Cissé · I. Cissé · L. Diop
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    ABSTRACT: Six acidic or neutral ethylenediaminetetraacetato [H2Y2-,H3Y- or Y4-] containing adducts and derivatives have been synthesized and studied by infrared. The suggested structures are discrete with octahedral or tetrahedral environments around the zinc centres, the ethylenediaminetetraacetic anion behaving as a bichelating, trichelating, tetrachelating and hydrogen bonds involved, pentachelating or hexachelating and hydrogen bonds involved ligand. For most of the structures when intermolecular hydrogen bonds are considered, a supramolecular architecture is obtained. © 2015 ALMA MATER Publishing House, “VASILE ALECSANDRI” University of Bacău. All rights reserved.
    No preview · Article · Jan 2015
  • Y. Sow · L. Diop
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    ABSTRACT: New oxalato and hydrogenoxalato organotin (IV) derivatives containing mono- and bichelating oxalates or a monochelating hydrogenoxalate, have been synthesized and characterized by elemental analyses, infrared and Mossbauer spectroscopy. The suggested structures are discrete, the environments around the tin (IV) atoms being trans octahedral, seven coordinated or tetrahedral. The cations when present are involved in NH…O bonds. A 1 D supramolecular architecture is suggested for SnPh2 (HC2O4)2 .1/2 C6H6. The C6H6 molecules obtained in situ molecules are lattice. SnPh3OH is involved in hydrogen bonding. © 2015 ALMA MATER Publishing House, “VASILE ALECSANDRI” University of Bacău. All rights reserved.
    No preview · Article · Jan 2015
  • Y. Sow · L. Diop
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    ABSTRACT: On allowing (Cy2NH2)2C2O4·2H2O to react with SnBu3Cl or SnMe3Cl, i-Bu2NH2HC2O4 with SnBu3Cl, (Bu2NH2)2C2O4 with SnMe3Cl, (i-Bu2NH2)2C2O4 with SnPh2Cl2, a mixture of i-Bu2NH2)2C2O4 and (Me4N)2C2O4 with SnPh2Cl2, (Pr2NH2)2C2O4 with SnPh3Cl, the oxalato derivatives and complexes Cy2NH2C2O4SnBu3.3H2O·1/4Cy2NH2Cl, i- Bu2NH2C2O4SnBu3·1/2(i-Bu2NH2)2C2O4,y2NH2C2O4SnMe3·1/2(Cy2NH2)2C2O4, Sn(C2O4)2·[C2O4(SnMe3·H2O)2]·2EtOH·1/4[(Bu2NH2)2C2O4],(i-Bu2NH2)2 C2O4·2SnPh2Cl2·SnCl4·4(i-Bu2NH2OH)·2(i-Bu2NH2Cl), 2[SnPh2Cl4(i-Bu2NH2)2]·SnCl2C2O4·4i-Bu2NH2Cl and 2[Pr2NH2C2O4SnPh3]·(Pr2NH2)2C2O4·SnCl4·2Pr2NH2Cl were obtained. Double chain, two metallic components and a dimeric structures are suggested with trans coordinated SnMe3 residues, these chains being connected through R2NH2+ (R = Cy, i-Bu) only or by (R2NH2)2C2O4 bridges. The oxalate behaves as a monochelating, a bridging, an only hydrogen bonding involved or monodentate and H bond involved ligand. The environments around the tin (IV) centres are cis or trans trigonal bipyramidal, tetrahedral or octahedral. Supramolecular architectures may be obtained when extra hydrogen bonds are possible. © 2015 ALMA MATER Publishing House, “VASILE ALECSANDRI” University of Bacău. All rights reserved.
    No preview · Article · Jan 2015
  • M. Sarr · A. Diasse-Sarr · L. Diop
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    ABSTRACT: On allowing PhPO3H2 to react with SnPh3Cl in ethanolic media, OC[OPOSnPh3OEt]2 is obtained by cetonization, desarylation and esterification, has been studied by infrared technic. A discrete structure has been suggested on the basis of infrared data, the anion behaving as a bidentate ligand, the environment around the tin centres being tertrahedral. © 2015 ALMA MATER Publishing House, “VASILE ALECSANDRI” University of Bacău. All rights reserved.
    No preview · Article · Jan 2015
  • Y. Sow · L. Diop
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    ABSTRACT: The reactions between (i-Bu2NH2)2C2O4, (Cy2NH2)2C2O4 .2H2O, (Pr2NH2)2C2O4, Pr2NH2HC2O4, (Me4N)2C2O4 .2H2O or Cy2NH2O2CPh and SnPh3Cl, SnBu3Cl or SnMe3Cl have yielded seven adducts that have been investigated by infrared and Mössbauer techniques. The suggested structures are discrete, the oxalate behaving as a non coordinating entity, only involved in hydrogen bonding while the benzoate is a mono-, bichelating or a monocoordinating ligand, the environments around the tin centres being trans or cis trigonal bipyramidal. When extra hydrogen bonds are considered involving free OH groups, a supramolecular architecture may be obtained. Noteworthy, is the key role of the cation and water molecules in the obtained structures. © 2015 ALMA MATER Publishing House, “VASILE ALECSANDRI” University of Bacău. All rights reserved.
    No preview · Article · Jan 2015
  • S. Cissé · I. Cissé · L. Diop
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    ABSTRACT: Nine acidic or neutral ethylenediaminetetraacetato [H2Y2-, H3Y- or Y4-] containing adducts and derivatives have been synthesized and studied by infrared. The suggested structures are discrete with octahedral or trigonal bipyramidal environments around the tin centres, the ethylenediaminetetraacetic anion behaving as a bidentate and hydrogen bonds involved, a tridentate, a tetradentate, a bichelating and hydrogen bonds involved ligand, a tri-or tetrachelating ligand. For all the structures when intermolecular hydrogen bonds involving OH or CH groups are considered, a supramolecular architecture may be obtained. © 2015 ALMA MATER Publishing House, “VASILE ALECSANDRI” University of Bacău. All rights reserved.
    No preview · Article · Jan 2015
  • Y. Sow · C.A.K. Diop · L. Diop · B. Mahieu · L. Stievano
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    ABSTRACT: The study of the interactions between C2O4(SnPh3)2 and a Lewis base (Ph3PO) or salts such as Ph4PCl, (Bu2NH2)2C2O4 .3H2O, (Pr2NH2)2C2O4(Cy2NH2)2C2O4 .2H2O have yielded seven new adducts, infrared and Mossbauer studies which have been carried out. The suggested structures are discrete or of infinite chain type. Most of the structures contain C2O4(SnPh3)2 with cis coordinated SnPh3 residues characterized for the first time in this work. In Ph3PO containing adducts the Lewis base coordinates a SnPh3 residue. The oxalate behaves as a mo- or bidentate, a mono- or bichelating, a only hydrogen bonds involved ligand. In the structures of the compounds containing a non symmetrical cation, this one is involved in N-H…O hydrogen bonds. © 2015 ALMA MATER Publishing House, “VASILE ALECSANDRI” University of Bacău. All rights reserved.
    No preview · Article · Jan 2015
  • Y. Sow · L. Diop · L. Stievano
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    ABSTRACT: A tetra- and a pentanuclear oxalato tin (IV) adducts, containing a tetradentate oxalate or a bi- and a tetradentate oxalates, have been synthesized and characterized by elemental analyses, infrared and Mossbauer spectroscopy. The suggested structures are polymeric. The environment around the tin centre is trigonal bipyramidal, the SnPh3 residue being dissymmetrically trans-coordinated. In the case of the pentanuclear adduct, the H2O molecule is involved O H…O hydrogen bonds. In these two adducts SnPh3OH behaves simultaneously as a Lewis acid and base.
    No preview · Article · Nov 2014 · Physical and Chemical News
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    ABSTRACT: The reaction of SeO4 H2 and SnPh3 OH in the presence of n-Bu2 NH led to the formation of [(n-Bu2 NH2)]3[SnPh3(SeO4)2] (1), which crystallizes in the orthorhombic space group P21 21 21 with Z=4, a=16.2509(7) Å, b=17.2412(8) Å, c=17.6881(5) Å, and V=4955.9(3) Å3. The structure of the novel trianion of 1 consists of a SnPh3 moiety trans-coordinated by two monodentate selenato ligands involving a trigonal bipyramid geometry around the Sn(IV) atom. The charges of [SnPh3(SeO4)2]3- are compensated by three [n-Bu2 NH2]+ cations. From a supramolecular point of view, the three uncoordinated oxygen atoms of each selenato ligand are involved in hydrogen bonding interactions with the surrounding di-n-butylammonium cations through N-H···O contacts, leading to a three-dimensional network. The structural characterization of salt 1 was completed by infrared and NMR spectroscopy and elemental analysis, which confirm the X-ray elucidation.
    No preview · Article · Jul 2014
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    ABSTRACT: The title compound, (C6H14N)2[Sn(C6H5)2Cl4], contains cyclo-hexyl-ammonium cations in general positions and a stannate(IV) anion that is located on a twofold rotation axis. The Sn(IV) atom in the complex anion is surrounded by four Cl(-) ligands and two trans-phenyl groups in a distorted octa-hedral configuration. The anions are connected with the cations through N-H⋯Cl hydrogen bonds. Every cation is involved in three N-H⋯Cl bonds to the chloride ligands of three different anions, and each chloride ligand is linked to two cations. This arrangement leads to a layered structure parallel to (010).
    Full-text · Article · Jun 2014 · Acta Crystallographica Section E Structure Reports Online
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    ABSTRACT: Single crystals of the title salt, C21H21NH(+)·Cl(-), were isolated as a side product from the reaction involving [(C6H5CH2)3NH]2[HPO4] and Sn(CH3)3Cl in ethanol. Both the cation and the anion are situated on a threefold rotation axis. The central N atom in the cation has a slightly distorted tetra-hedral environment, with angles ranging from 107.7 to 111.16 (10)°. In the crystal, the tri-benzyl-ammonium cations and chloride anions are linked through N-H⋯Cl and C-H⋯Cl hydrogen bonds, leading to the formation of infinite chains along [001]. The crystal studied was a merohedral twin.
    Full-text · Article · May 2014 · Acta Crystallographica Section E Structure Reports Online