- Structural chemistry of (PPh4)2M(WS4) 2 materials
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In this paper we discuss the structural chemistry of (PPh4) 2M(WS4)2 (M = Co, Ni, Zn) materials. For M = Ni we and others have been unable to grow single crystals and we report the structure determination from powder diffraction. The material is triclinic (PI, a = 9.3730(2), b = 12.4951(3), c = 12.5189(3) Ae, α = 65.814(1), β = 83.751(1), γ = 69.571(1)° at T = 293 K). It contains square-planar coordination around Ni. For M = Zn we have isolated two polymorphs. We describe new analysis of the complex superstructure and diffuse scattering observed in the tetragonal polymorph (I4, a = 18.723(4), c = 13.563(4) Ae at T = 120 K) and the bulk preparation of a monoclinic (P2 1/c, a = 18.6397(4), b = 15.3693(5), c = 18.9822(5) Ae, β = 109.239(2)° at T = 293 K) polymorph isostructural with the M = Co material. The Royal Society of Chemistry.
- Crossland, Clare J.,Evans, Ivana Radosavljevic,Evans, John S. O.
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- Synthesis, characterization and biological evaluation of octyltrimethylammonium tetrathiotungstate
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Abstract: Octyltrimethylammonium tetrathiotungstate salt (ATT-C8) was synthesized and its ability to chelate copper was evaluated. The biological and toxic aspects were evaluated by in vitro and in vivo assays, using bovine aorta endothelial cells (BAEC) and zebrafish (Danio rerio) embryos. The obtained results suggest that ATT-C8 has better biocompatibility, showing a significantly lower lethal concentration 50 (LC50) value in comparison to ammonium tetrathiotungstate (ATT). Zebrafish embryos assay results indicate that both tetrathiotungstate salts at the studied concentrations increase the hatching time. Even more, an in vivo assay showed that synthesized materials behave as copper antagonists and have the ability to inhibit its toxicological effects. Also, both materials were found to be active for the in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The characterization of the materials was carried out using the following spectroscopic techniques: Ultraviolet–Visible (UV–Vis), Fourier Transform Infrared (FTIR) and proton nuclear magnetic resonance (1H-NRM). Graphic abstract: [Figure not available: see fulltext.]
- Vega-Granados, Karla,Cruz-Reyes, Juan,Horta-Marrón, José F.,Marí-Beffa, Manuel,Díaz-Rubio, Laura,Córdova-Guerrero, Iván,Chávez-Velasco, Daniel,Oca?a, M. Carmen,Medina, Miguel A.,Romero-Sánchez, Lilian B.
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- Two cation disulfide layers in the WxMO(1-x)S2 lamellar solid solution
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WxMo(1-x)S2 compounds with both molybdenum and tungsten present in every disulfide layer, i.e., as an intralayer solid solution, can be obtained. Several synthesis routes have been used but all of them do not allow this solid solution, which evidences the decisive role of the nature of the precursor, to be obtained. We never observed formation of a WxMo(1-x)S2 solid solution resulting from stacking of homocationic [WS2] and [MoS2] layers (interlayer solid solution).
- Thomazeau, Cecile,Geantet, Christophe,Lacroix, Michel,Harle, Virginie,Benazeth, Simone,Marhic, Christiane,Danot, Michel
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- Dimeric Tungsten(V) Compounds Containing 2+. Syntheses and Structures of Di-μ-sulphido-bis and Di-μ sulphido-bis
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The compounds 2> has been isolated by two alternative routes: (a) treatment of 2- with HS2P(OEt)2 and (b) reaction of WS2Cl2 with .The oxidation product of both reactions is 2.The two routes led to two different crystal forms, (1a) and (1b), of the product 2>.Treating 2>, either form, with Na(S2CNEt2) gave (2).The crystal structures of (1a), (1b), and (2) have been determined. (1a) is monoclinic, space group P21/n, with a=18.230(11), b=12.905(11), c=10.153(12) Angstroem, β=90.5(1) deg and Z=4; (1b) is monoclinic, space group P21/a with a=13.844(12), b=10.280(9), c=17.907(13) Angstroem, β=113.2(1) deg, and Z=4; (2) is orthorhombic, space group P212121, with a=13.80(1), b=10.49(1), c=14.59(1) Angstroem, and Z=4.Diffractometer data were collected for all three compounds , the structures determined by the heavy-atom method and refined to give R=0.061, 0.084, and 0.066 for (1a), (1b), and (2) respectively.All three compounds contain the syn form of 2+ , 2.279(8)-2.325(9) , and 2.795(2)-2.819(1) Angstroem (W-W)>.In addition to the bonds in the 2+ moiety, each tungsten atom is co-ordinated to a bidentate ligand with W-S bond lengths in the range 2.429(9)-2.498(6) Angstroem.Apart from the W-W bond each metal atom is five-co-ordinate and has a distorted square-pyramidal structure.
- Drew, Michael G. B.,Hobson, Richard J.,Mumba, Peter P. E. M.,Rice, David A.,Turp, Neil
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p. 1163 - 1168
(2007/10/02)
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- Facile syntheses of new molybdenum and tungsten sulfido complexes. Structure of Mo3S92-
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Heating (NH4)2MS4 (M = W, Mo) in N,N-dimethylformamide leads to the formation of the trinuclear ions M3S92-. Under similar conditions but in the presence of 1,2-ethanedithiol (edtH2) or o-aminobenzenethiol (abtH2) the dinuclear ions M2S4(edt)22- or M2S4(abt)22- are formed. The complex (PPh4)2Mo3S9 (Ph = C6H5) crystallizes in the space group P1 (Z = 1) with unit cell dimensions a = 9.100 (2) ?, b = 10.531 (5) ?, c = 13.286 (6) ?, α = 87.02 (4)°, β = 84.99 (2)°, and γ = 83.56 (2)°. The structure shows two external tetrahedral MoS4 units chelating a central square-pyramidal MoS unit. The Mo-Mo-Mo angle is 155.0 (1)°. Key distances (A) are as follows: Mo-S(terminal to central Mo) = 2.086 (4); Mo-S(terminal to external Mo) = 2.134 (4), 2.145 (4), 2.136 (3), 2.148 (3); Mo-S(bridge to external Mo) = 2.231 (3), 2.247 (3), 2.251 (3), 2.234; Mo-S(bridge to central Mo) = 2.429(3), 2.369 (3), 2.389 (3), 2.388 (3); Mo-Mo = 2.982 (1), 2.924 (1). The cyclic voltammetry of the trinuclear complexes is reported. The complexes M3S92- are formulated as mixed-valence VI, IV, VI compounds, and a mechanism is proposed for their formation.
- Pan, Wie-Hin,Leonowicz, Michael E.,Stiefel, Edward I.
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p. 672 - 678
(2008/10/08)
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