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Based on the ligand 1,2-H2bdc (1,2-H2bdc = 1,2-benzenedicarboxylic acid), three 2D coordination polymers [Mn(1,2-bdc)]n (1), [Cu(1,2-bdc)]n (2) and [Co3(OH)2(1,2-bdc)2]n (3), have been prepared and characterized. In comparison with the mononuclear Mn unit of compound 1, paddle-wheel binuclear Cu2(CO2)4 and trinuclear Co3(OH) building units are observed in 2 and 3, respectively. Also, the bdc2− ligands adopt different coordination modes in the three compounds. The resulting two frustrated lattices have been observed, such as the triangular lattice for 2 and the Kagomé lattice for 3, and thus, both complexes 2 and 3 show spin frustrated antiferromagnetic properties. In addition, the magnetic hysteresis loops reveal the existence of the long range ordering in 2 and 3. Comparatively, the magnetic measurements indicate that compound 1 exhibits a weak antiferromagnetic interaction, and the fit of the variable-temperature magnetic susceptibility data to the empirical equation leads to the following parameters: J = −0.80(1) cm−1 and g = 2.02. [ABSTRACT FROM AUTHOR]

A 2-D coordination polymer, (C7N4H16)2{NH(CH3)3}[{K(H2O)}4Na(H2O)5{Co4(H2O)2(B-a-PW9O34)2}]·2H2O (1), was hydrothermally synthesized and structurally characterized by IR spectroscopy, elemental analysis, X-ray powder diffraction, and X-ray single-crystal crystallography. Crystal structure analysis shows a triclinic space group Pī with a=12.4677(8)Å, b=12.5054(8)Å, c=18.5745(1)Å, a=73.3220(1)°, ß=87.1890(1)°, ?=62.2710(1)°, and V=2443.4(3)Å3. Sandwich-type tetra-cobalt(II)-substituted [Co4(H2O)2(B-a-PW9O34)2]10- of 1 consists of two trivacant Keggin [B-a-PW9O34]9- moieties and a rhomb-like Co4O16 unit. Each sandwich-type polyoxotungstate subunit connects 12 K(1) and K(2) centers from two adjacent 1-D K-chain units resulting in an interesting 2-D layer framework. Magnetic properties of 1 have been investigated. [ABSTRACT FROM AUTHOR]

Three new B-Anderson type polyoxometalates, [(C6H5NO2)2Ln(H2O)6](CrMo6O24H6)·2C6H5NO26H2O (Ln=Sm 1, Dy 2 and Er 3), have been synthesized in aqueous solution and structurally characterized by single-crystal X-ray diffraction, IR spectra, UV spectroscopy, and fluorescence spectroscopy. Crystal structure analysis reveals that these three compounds have the same composition and are isostructural, assembled by B-Anderson type polyoxoanion [CrMo6O24H6]3-, rare-earth ions, and ligands. UV spectroscopy shows that 1 is stable when pH is 4.50-5.83. The fluorescence spectra of 2 indicate that both rare-earth ions Dy3+ and pyridine-4-carboxylic acid ligands function in the charge transition of the compound [ABSTRACT FROM AUTHOR]

Nickel complex formulated as Ni(L)2 (L = monodeprotonated ligand corresponding to 2-acetylpyridine N(4)-methylthiosemicarbazone, HL) has been synthesized and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. The complex consists of discrete monomeric molecules with octahedral nickel(II) with two anionic 2-acetylpyridine N(4)-methylthiosemicarbazones as NNS tridentate ligands coordinated to nickel via the pyridine nitrogen, azomethine nitrogen, and sulfur. Hydrogen bonds link the different components to stabilize the crystal structure. Biological studies, carried out in vitro against bacteria, fungi, and the K562 leukemic cell line have shown that the free ligand and complex show distinct differences in biological activity. [ABSTRACT FROM AUTHOR]

Transition metal complexes [Fe(HL)2]Cl3 ⋅ 1.5H2O (1), [Co(L)2] ⋅ ClO4 ⋅ H2O (2), Ni(HL)2(ClO4)2 ⋅ 2H2O (3), Zn(HL)L ⋅ BF4 ⋅ 2H2O (4), and Cd(HL)2(ClO4)2 ⋅ 2H2O (5), where HL = C7H9N5S, 2-acetylpyrazine thiosemicarbazone, have been synthesized. Complex 2 was characterized by elemental analysis, infrared spectra, mass spectra, and single-crystal X-ray diffraction. Preliminary in vitro screening showed that 1, 4, and 5 exhibit higher antitumor activity than 2 and 3 against K562 leucocythemia cancer cell line. [ABSTRACT FROM AUTHOR]

A new organic-inorganic hybrid material constructed from octamolybdate anion and neutral dinuclear copper(I) units, H4{[Cu2(ophen)2]2[Mo8O26]}[Cu2(ophen)2] · H2O (1) (Hophen =2-hydroxy-1,10-phenanthroline), has been prepared under hydrothermal condition and characterized by elemental analysis, IR, XPS, TGA and single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P1, with a = 9.9091(8), b = 13.3981(8), c = 14.8266(10) Å, α = 84.6310(10), β = 83.0620(10)°, γ = 77.7800(10), V = 1905.0(2) Å3, Z = 1. Compound 1 contains a centrosymmetric polyoxoanion {[Cu2(ophen)2]2[Mo8O26]}4-, in which the β-[Mo8O26]4- is bisupported by two copper(I) coordination groups through the terminal oxygen atoms. The discrete molecules of 1 are extended into a 3-D supramolecular array through C-H ··· O hydrogen bonds and strong aromatic π-π stacking contacts. [ABSTRACT FROM AUTHOR]

A new organic-inorganic hybrid compound constructed from Keggin-type polyanion clusters and transition metal complexes, [Co(2,2'-bipy)3]1.5[SiWVWVI11O40Co(2,2'-bipy)2(H2O)] · 0.5H2O (1), has been hydrothermally prepared and characterized by elemental analysis, IR, UV-Vis, TG-DTA and single crystal X-ray diffraction. Compound 1 crystallized in the monoclinic system, space group C2/c, a = 46.995(15), b = 14.487(5), c = 26.205(9)Å, β = 90.000(0)°, V = 17841(10)Å3, Z = 4. Compound 1 contains a [SiWVWVI11O40Co(2,2'-bipy)2(H2O)]3- polyoxoanion in which [Co(2,2'-bipy)2(H2O)]2+ is covalently bonded to the α-Keggin-type heteropolyanion [SiWVWVI11O40]5- via a terminal oxygen. [ABSTRACT FROM AUTHOR]

The reaction of α-[SiMo12O40]4- with trivalent cations Ln3+ and N-methyl-2-pyrrolidone leads to a series of complexes of formula [Ln(NMP)4(H2O)n]H[SiMo12O40] · 2NMP · mH2O [where Ln = La (1), Pr (2), Nd (3), Sm (4), Gd (5), n = 4, Ln = Dy (6), Er (7), n = 3. NMP = N-methyl-2-pyrrolidone]. The syntheses, X-ray crystal structures, IR, and ESR spectra and thermal properties of the complexes 1, 2, 4, 6, 7 have been reported previously. Here, we report X-ray crystal structures, IR, UV, ESR spectra and thermal properties of the complexes [Nd(NMP)4(H2O)4]H[SiMo12O40] · 2NMP · 1.5H2O (3), and [Gd(NMP)4(H2O)4]H[SiMo12O40] · 2NMP · H2O (5). In addition, the electrochemical behaviour of this series of complexes in aqueous solution and aqueous-organic solution has been investigated and systematic comparisons have been made. All these complexes exhibit successive reduction process of the Mo atoms. [ABSTRACT FROM AUTHOR]

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, Dc = 2.116 Mg m-3, R = 0.0748, wR2 = 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. [ABSTRACT FROM AUTHOR]