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Chemistry 05/2010; 16(24):7082-6. · 5.93 Impact Factor
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ABSTRACT: [Fe(HL)2]Cl3 · 1.5H2O (1), where HL = C7H9N5S, 2-acetylpyrazine thiosemicarbazone, was obtained and fully characterized. X-ray diffraction studies show that complex 1 crystallizes in monoclinic lattice, space group P21 /n, with a = 11.342(6), b = 12.547(6), c = 17.056(9) Å, β = 103.551(7)°, V = 2360(2) Å3, Z = 2, Mr = 1159.46, D Calcd = 1.632 g cm−3, μ(Mo-Kα) = 1.188 mm−1, F(000) = 1184, the final R 1 = 0.0955 and wR 2 = 0.2626. The 2-acetylpyrazine thiosemicarbazone is a tridentate ligand and binds to the metal through the pyrazine nitrogen, the imine nitrogen and the sulfur in the neutral thione form yielding an octahedral geometry. The title iron complex showed significant antitumor activity against the Ec9706 human esophagus cancer cell line with an IC50 value (10.50 µM) in a micromolar range similar to cisplatin.
Journal of Coordination Chemistry 05/2009; 62(9):1423-1429. · 1.55 Impact Factor
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ABSTRACT: Rational self-assembly of Sb(2)O(3) and Na(2)WO(4), or (NH(4))(18)[NaSb(9)W(21)O(86)] with transition-metal ions (Mn(2+), Cu(2+), Co(2+)), in aqueous solution under controlled conditions yield a series of sandwich type complexes, namely, Na(2)H(2)[Mn(2.5)W(1.5)(H(2)O)(8)(B-beta-SbW(9)O(33))(2)]32 H(2)O (1), Na(4)H(7)[Na(3)(H(2)O)(6)Mn(3)(mu-OAc)(2)(B-alpha-SbW(9)O(33))(2)]20 H(2)O (OAc=acetate anion) (2), NaH(8)[Na(2)Cu(4)Cl(B-alpha-SbW(9)O(33))(2)]21 H(2)O (3), Na(8)K[Na(2)K(H(2)O)(2){Co(H(2)O)}(3)(B-alpha-SbW(9)O(33))(2)] 10 H(2)O (4), and Na(5)H[{Co(H(2)O)(2)}(3)W(H(2)O)(2)(B-beta-SbW(9)O(33))(2)]11.5 H(2)O (5). These structures are determined by using the X-ray diffraction technique and further characterized by obtaining IR spectra and performing elemental analysis. Structure analysis reveals that polyoxoanions in 1 and 5 comprise of two [B-beta-SbW(9)O(33)](9-) building units, whereas 2, 3, and 4 consist of two isomerous [B-alpha-SbW(9)O(33)](9-) building blocks, which are all linked by different transition-metal ions (Mn(2+), Cu(2+), or Co(2+)) with different quantitative nuclearity. It should be noted that compound 2 represents the first one-dimensional sinusoidal chain based on sandwich like tungstoantimonate building blocks through the carboxylate-bridging ligands. Additionally, 3 is constructed from sandwiched anions [Na(2)Cu(4)Cl(B-alpha-SbW(9)O(33))(2)](9-) linked to each other to form an infinitely extended 2D network, whereas 5 shows an interesting 3D framework built up from offset sandwich type polyoxoanion [{Co(H(2)O)(2)}(3)W(H(2)O)(2)(B-beta-SbW(9)O(33))(2)](6-) linked by Co(2+) and Na(+) ions. EPR studies performed at 110 K and room temperature reveal that the metal cations (Mn(2+), Cu(2+), Co(2+)) reside in a square-pyramidal geometry in 2, 3, and 4. The magnetic behavior of 1-4 suggests the presence of weak antiferromagnetic coupling interactions between magnetic metal centers with the exchange integral J=-0.552 cm(-1) in 2.
Chemistry - An Asian Journal 06/2008; 3(5):822-33. · 4.50 Impact Factor
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ABSTRACT: Two sandwich-type tungstoantimonates K4Na2H3[Na2K(H2O)2{Cu(H2O)}3(α-SbW9O33)2] · 15H2O (1) and Na4H4[{Ni(H2O)3}2{W(OH)2}2{β-SbW9O33}2] · 23H2O (2) were prepared from aqueous solution by different strategies. They were characterized by X-ray structure analysis, electrochemical analysis, EPR and IR spectroscopy. Both compounds are sandwich-like tungstoantimonates built from two B-[SbW9O33]9− building blocks. The polyoxoanion of 1 consists of two trivacant B-α-[SbW9O33]9− moieties linked by three Cu2+ ions leading to a Hervé-type sandwich framework. The polyoxoanion in 2 is composed of two isomeric B-β-[SbW9O33]9− subunits joined together by two Ni2+ and two W6+ ions resulting in a Krebs-type sandwich structure.
Journal of Coordination Chemistry. 03/2008; 61(6):936-944.
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ABSTRACT: A new organic–inorganic polyoxometalate compound [Co(2,2′-bipy)3]H[Al(OH)6 (Mo6O18)] · 17H2O has been synthesized and characterized by elemental analysis, IR, UV spectra, thermogravimetry and differential thermal analysis (TG-DTA) and single-crystal X-ray diffraction analysis. The title compound crystallizes in a monoclinic, C2/c space group, with a = 37.292(8), b = 14.214(3), c = 25.050(5) Å, β = 120.62(3), V = 11426(4) Å3, Z = 8, F(000) = 7200, D c = 2.116 Mg m−3, R = 0.0748, wR 2 = 0.1853. Crystal structural analysis indicates that the asymmetric unit in the crystal structure of the title compound consists of one B-Anderson–Evans type heteropolyoxoanion, one octahedral [Co(2,2′-bipy)3]2+ coordination cation, seventeen water molecules of crystallization and a proton based on charge balance. The curves of TG-DTA indicate that weight loss of the title compound is divided into three stages. The third weight loss reveals that the backbone of heteropolyoxoanion decomposes at 744°C.
Journal of Coordination Chemistry. 06/2007; 60(12):1327-1334.
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ABSTRACT: The title compound, bis[tris(2,2'-bipyridine)iron(II)] tetraaquatetra-mu4-oxo-pentacosa-mu2-oxo-undecaoxoiron(III)sodium(I)dodecatungsten(VI) dihydrate, [Fe(C10H8N2)3]2[NaFeW12O40(H2O)4].2H2O, consists of a dodecatungstoferrate(III) framework grafted on to an [Na(H2O)4]+ cation, two complex [Fe(2,2'-bipy)3]2+ cations (2,2'-bipy is 2,2'-bipyridine) and two uncoordinated water molecules per formula unit.
Acta Crystallographica Section C Crystal Structure Communications 01/2007; 62(Pt 12):m604-6. · 0.52 Impact Factor
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ABSTRACT: Five novel polyoxometalate compounds built on the lacunary Keggin-type polyanion [GeW11O39]8- and trivalent rare earth ions (M = Nd, Sm, Y, Yb), [(CH3)4N]2H1.50[Nd1.50(GeW11O39)(H2O)6]·3H2O (1), [(CH3)4N]2H2.25[Sm1.25(GeW11O39) (H2O)4]·3.75H2O (2), [(CH3)4N]2.50H2.50[Y(GeW11O39)(H2O)2]·4H2O (3), [(CH3)4N]2.50H2.50Yb(GeW11O39)(H2O)2]·3.75H2O (4), and [Sm(H2O)7]0.5H0.5[Sm2(GeW11O39)(DMSO)3(H2O)6]·3.5H2O (5) (DMSO = dimethyl sulfoxide) have been synthesized and characterized by elemental analysis, IR and UV spectroscopy, and single-crystal X-ray diffraction. The solid-state structures of compounds 1 and 2 consist of one-dimensional zigzag chains built of [α-GeW11O39]8- anions connected by Nd3+/Sm3+ cations, while the linkage of the building blocks by Y3+/Yb3+ centers in 3 and 4 leads to the formation of linear wires. Compound 5 displays a double-parallel chainlike structure constructed by two linear wires linked by samarium coordination cations.
09/2006;
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ABSTRACT: Three novel organic−inorganic hybrid monovacant Keggin-type silicotungstates and germanotungstates containing lanthanideIII cations with 1D and 2D infinitely extended structures, [Sm(H2O)6]0.25[Sm(H2O)5]0.25H0.5{Sm(H2O)7[Sm(H2O)2(DMSO)(α-SiW11O39)]}·4.5H2O (DMSO = dimethyl sulfoxide) (1), [Dy(H2O)4]0.25[Dy(H2O)6]0.25H0.5{Dy(H2O)7[Dy(H2O)2(DMSO)(α-GeW11O39)]}·5.25H2O (2), and H{[Sm(H2O)5.5(DMF)0.5]2[Sm(H2O)2(DMF)][Sm(H2O)3(α-SiW11O39)]2} (DMF = N,N-dimethyl formamide) (3), have been synthesized in aqueous solution under moderate conditions and further characterized by elemental analyses, inductively coupled plasma (ICP) analyses, IR, UV spectra, and X-ray diffraction. Compounds 1 and 2 reveal the one-dimensional chain infinitely extended structure, while compound 3 represents the first example of a two-dimensional network structure formed by the monovacant Keggin-type [α-SiW11O39]8- chain through the linkage of rare earth metal−organic coordination cations. From thermogravimetric (TG/DTA) analyses, the polyanion frameworks of 1 and 2 retain a comparatively good thermal stability. Variable temperature magnetic susceptibility indicates that compounds 1 and 3 obey the Curie−Weiss law in the higher temperature region from 130 to 300 K, while in the lower temperature region from 2 to 130 K they show the occurrence of strong spin−orbital coupling interactions and very weak ferromagnetic responses.
01/2006;
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ABSTRACT: A new composite complex of the general formula [Yb(DMSO)7]H[SiMo12O40] has been synthesized from H4SiMo12O40⋅nH2O, YbCl3 and DMSO in mixed solvent of acetonitrile and water and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. Singe crystal X-ray structure analysis shows that it belongs to monoclinic system, space group P21/c, with a = 11.685(2) , b = 14.969(3) , c = 35.037(7) , β = 98.50(3)∘, and Z = 4. There is one [Yb(DMSO)7]3+ coordinated cation and one [SiMo12O40]4− polyanion in one structure unit. The organic ligands (DMSO) do coordinate directly with ytterbium(III) to form a distorted pentagonal bipyramid complex ion by coordination bond, then combines to the SiMo12O404− anion by static electric force. The results of IR and X-ray diffraction show that there is strong interaction between polyoxometalate and organic donors.
Journal of Chemical Crystallography 12/2004; 35(8):629-634. · 0.57 Impact Factor
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ABSTRACT: Two composite compounds, [{Ce(DMF)4(H2O)3}{Ce(DMF)4(H2O)4}(P2W18O62)]·H2O (1) (DMF = N,N-dimethylformamide) and [{La(DMF)6(H2O)}{La(DMF)4.5(H2O)2.5}·(P2W18O62)] (2), have been constructed at room temperature and characterized by single crystal X-ray structural analyses, ESR spectroscopy, and thermogravimetric (TG) and differential thermal analysis (DTA) measurements. Single crystal X-ray structural analyses reveal that the adjacent polyanions are polymerized to form a 1D infinitely linear chain by the bridging RE coordination cations and exhibit an -ACACAC- type of structure, and that two types of terminal oxygen atoms of the Wells−Dawson polyanion located in the “cap” and “belt” sites are involved in coordination with the RE3+ ions, respectively. ESR spectra indicate that after irradiation with sunlight, compound 2 forms a mixed-valence heteropoly compound with unshared electrons. From TG-DTA analyses, we surmise that the frameworks of polyanions of this kind of compound decompose at ca. 620 °C.
01/2004;
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ABSTRACT: The structures of three 1:1 composite compounds prepared with the polyoxometalate (POM) [PMo12O40]3− and the cations [Ln(NMP)6]3+ [Ln = La (1), Ce (3), Pr (2); NMP = N-methyl-2-pyrrolidone] exhibit two types of zig-zag chains with alternating cations and anions through Mo−Ot−Ln−Ot−Mo links in the crystal. The compounds were characterized by IR, UV, and ESR spectroscopy, single-crystal X-ray structural analysis, and by a study of their thermal properties. In all the compounds, the La3+, Pr3+, and Ce3+ centers are eight-coordinate with the oxygen atoms in bicapped trigonal-prismatic geometries. The variation of the average Ln−O separations along the La, Ce, and Pr series is consistent with the effects of the lanthanide contraction. The results of the single-crystal X-ray diffraction analyses and the IR spectroscopic studies are in agreement and both show the metal cation units are coordinatively bonded to the Keggin clusters. The UV spectra of the title compounds suggest that their structures are entirely disrupted in dilute solution. Low-temperature ESR spectra indicate that thermal electron delocalization occurs among the Mo atoms in the three compounds. The results of cyclic voltammetry (CV) show that compounds 1, 2, and 3 all undergo five two-electron reversible reductions and that the [PMo12O40]3− anions are the active centers for electrochemical redox reactions in solution, while the corresponding cations have only a small effect on the electrochemical properties. Studies of magnetic properties show that 1 is diamagnetic, while 2and 3 exhibit antiferromagnetic Pr−Pr or Ce−Ce exchange interactions. In addition to the results of CV, the average bond lengths and the magnetic properties of compound 3 indicate that the oxidation state of cerium is III in the compound of formula [{Ce(NMP)6}(PMo12O40)]n. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Berichte der deutschen chemischen Gesellschaft 10/2003; 2004(1):160 - 170. · 2.94 Impact Factor
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Journal of Coordination Chemistry. 04/2003; 56(6):523-530.
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Journal of Coordination Chemistry. 04/2001; 53(2):153-162.
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ABSTRACT: A novel compound, [{Gd(NMP)6}(PMo12O40)]n, has been synthesized and characterized by IR, and UV spectroscopy, and single crystal X-ray structural analysis. It forms an unprecedented one-dimensional zigzag chain built from alternating polyanions and cationic units through Mo–Ot–Gd–Ot–Mo links in the crystal. In the compound, Gd3+ is eight-coordinated with a bicapped trigonal prism geometry environment of oxygen atoms. The results of the single crystal X-ray diffraction analyses and IR are agreement and both show the metal cation units are coordinately bonded to the Keggin cluster. The UV spectrum of the title compound suggests that the compound is entirely dissociated in dilute solution.
Journal of Molecular Structure.
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ABSTRACT: A novel compound, [{Pr(DMSO)6(H2O)}(PMo12O40)·CH3CN]n, has been synthesized and characterized by IR and single crystal X-ray structural analysis. It forms an one-dimensional zigzag chain built from alternating polyanions and cationic units through Mo–Ot–Pr–Ot–Mo links in the crystal. The results of the single crystal X-ray diffraction analyses and IR are agreement and both show the metal cation units are coordinately bonded to the Keggin cluster. The low temperature ESR spectrum indicates thermal electron delocalization occurs among the Mo atoms in the compound. The result of CV shows that the title compound undergoes five two-electron reversible reductions and that [PMo12O40]3− anions are active centre for electrochemical redox in the solutions, while matched cations have small effect on electrochemical redox.
Journal of Molecular Structure.
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ABSTRACT: The title complex [Co(L) 2 ]Cl·4H 2 O I has been achieved via self-assembly by incorporating cobalt into 2-benzoylpyridine thiosemicarbazonate ligand, and characterized by elemental analysis, infrared spectra, mass spectra and single-crystal X-ray diffraction study. The crystal crystallizes in monoclinic, space group P2 1 /n, with a = 10.227(3), b = 17.363(4), c = 17.459(4) Å, β = 100.408(4)º, V = 3049.2(13) Å 3 , Z = 4, M r = 677.08, D c = 1.475 g/cm 3 , µ(MoKα) = 0.834 mm −1 , F(000) = 1400, the final R = 0.0747 and wR = 0.0896 for 1663 observed reflections with I > 2σ(I). The complex contains one six-coordinated cobalt ion connected by two thiosemicarbazone ligands which act as a tridentate ligand to coordinate with the center metal atoms via two pyridyl nitrogen atoms, two imine nitrogen atoms and two sulfur atoms giving rise to a mononuclear structure. Hydrogen bonds existing in the complex link the different com-ponents to stabilize the crystal structure. The antitumor activity of the title complex was tested against A549 lung cancer cell line. Complex I exhibits antitumor activity.
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Inorganic Chemistry Communications 10(12):1391-1393. · 1.97 Impact Factor
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ABSTRACT: The reaction of the mono-lacunary silicotungstate ligand α-K8SiW11O39 · 13H2O with praseodymiumIII cation results in a new Keggin-type derivative K3[(Pr(H2O)4SiW11O39)(NaPr2(H2O)12)(Pr(H2O)4SiW11O39)] · 13.5H2O (1), whose polyanion consists of two crystallographically distinct [Pr(H2O)4SiW11O39]5− building block units and one [NaPr2(H2O)12]7+ subunit, which are connected by alternating praseodymium and sodium centers via the terminal and bridging oxygen atoms from the precursor [α-SiW11O39]8− to construct a 1D infinitely chainlike structure.
Inorganic Chemistry Communications 7(7):876-879. · 1.97 Impact Factor
