Synthesis and Antibacterial Activity of Polyoxometalates with Different Structures.

A new inorganic-organic hybrid compound, [{Cu(phen)2}2(H4W12O40)], was synthesized, and its crystal structure was determined. The Keggin anion H4W12O40 4- was grafted with two coordination units {Cu(phen)2}, forming an electrically neutral molecule. The antibacterial activity of several polyoxometalate compounds with different anionic structures including the new compound was studied. The results show that the compound 1 can inhibit the growth of Enterococcus faecalis FA2 strains and that antibacterial activity of the polyoxometalate compounds is dependent with component elements of POM but is less relative with the anion structures.

A Novel Application of Ti-Substituted Polyoxometalates: Anti-Inflammatory Activity in OVA-Induced Asthma Murine Model.

Objective. Asthma is a chronic inflammatory disorder. Despite extensive researches into the treatment and management of it, current treatments and management strategies are still limited. The search for a novel approach to its treatments is urgently needed. Researches on the potential medical use of polyoxometalates (POMs) have already shown it has antiviral and antitumor bioactivities. But the effects of POM in immune systems are still largely unknown. Methods. In order to investigate the role of POM in the asthmatic disease, we used OVA-induced asthma murine model and observed the pathological changes between mice that received three different Ti-substituted POMs (0.3 µg per mouse per dose) when challenged with OVA. We also measured the type 2 cytokine expressions to reveal the potential mechanism. Results and Conclusions. Our results showed that two Ti-substituted POMs, K5H2[FeW11TiO40]·17H2O and K5H[H2ZnW11TiO40]·35H2O, could reduce OVA-induced lung inflammation, serum IgE level (around 2000 ng/mL to less than 1000 ng/mL), leukocytes infiltration in the lung, and cytokines levels (including IL-4, IL-5, IL-13, and TNF-α) but Ti-centered POM K4[TiW12O40]·10H2O did not. Thus, Ti-substituted POMs may have pharmaceutical values especially in treatments for asthmatic diseases.

Two Compounds Constructed from Bimolybdenum-Capped Sandwich-Type Tetra-Ni-molybdogermanate and N-Donor Multidentate Ligand.

Two organic-inorganic hybrid bimolybdenum-capped tetra-Ni(II) sandwich-type molybdogermanates, namely, (H2L)4[Ni4(H2O)2{B-α-GeMo9O34 (MoO2)}2]·6H2O (1), [Ni2(HL)4(H2O)2][Ni4(H2O)2{B-α-GeMo9O34(MoO2)}2]·12H2O (2), L = 2,4,5-tri(4-pyridyl)imidazole, were prepared with hydrothermal synthesis method and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, thermogravimetric analysis, and single-crystal X-ray diffraction. Their magnetic properties and electrochemical properties were investigated. The results show that compounds 1 and 2 contain a new bimolybdenum-capped sandwich-type heteropolymolybdate anion, [Ni4(H2O)2{B-α-GeMo9O34(MoO2)}2](8-). The compound 1 is a zero-dimensional supramolecular compound, and the supramolecular architecture of compound 2 is constructed from covalent layers through hydrogen bonds and π-π interaction. The two compounds both present electrocatalytic activities for the reduction of nitrite.

Functionalized pentamolybdodiphosphate-based inorganic-organic hybrids: synthesis, structure, and properties.

Three inorganic-organic hybrid compounds based on functionalized pentamolybdodiphosphonopropionate anion [(HO2CC2H4PO3)2Mo5O15](4-), [Co3(bipy)4(H2O)6{(HO2CC2H4PO3)2Mo5O15}2]·(H2bipy)2·18H2O (1), [Fe3(bipy)4(H2O)6{(HO2CC2H4PO3)2Mo5O15}2]·(H2bipy)2·18H2O (2), and [Cu(bipy)(H2O)2{(HO2CC2H4PO3)2Mo5O15}]·(H2bipy)·4H2O (3), where bipy = 4,4'-bipyridine, have been successfully synthesized at different pH values in aqueous solutions. In compound 1, [(HO2CC2H4PO3)2Mo5O15](4-) acts as a tridentate ligand and coordinates to the Co(2+) ions of trimeric complex cations [Co3(bipy)4(H2O)6](6+) forming a layer. In 3 [(HO2CC2H4PO3)2Mo5O15](4-) acts as a bidentate ligand and coordinates to the Cu(2+) ions of complex chains [Cu(bipy)(H2O)2]n(2n+), forming a different layer from that in 1. The three compounds were characterized by elemental analysis, IR spectra, and TGA. In addition, their fluorescent properties and magnetic properties have also been investigated.

A feasible route to approach 3D POM-based hybrids: utilizing substituted or reduced Keggin anions with high charge density.

Five new hybrid compounds based on Keggin polyanions, Ag(+)/Cu(+) ions and 1,3-bis(1,2,4-triazol-1-yl)propane (btp) molecules have been hydrothermally synthesized. In [Ag(5)(btp)(4)(H(2)O)(2)][PCuW(11)O(39)]·2H(2)O (1), [Ag(4.33)Na(0.67)(btp)(4)(H(2)O)(2)][PMnMo(11)O(39)]·H(2)O (2) and [Cu(4)(btp)(4)Na(H(2)O)(2)][PMnMo(11)O(39)]·2H(2)O (3), the neighboring mono-substituted Keggin clusters are alternately connected via sharing oxygen atoms to form an unusual Keggin-based transition-metal monosubstituted chain, in which the Keggin cluster serves as a decadentate ligand and grafts ten metal atoms representing the highest connected number for Keggin cluster and forming a 3D framework. In [Ag(5)(btp)(4)][PW(VI)(10)W(V)(2)O(40)] (4) and [Ag(5)(btp)(4)][PMo(VI)(10)Mo(V)(2)O(40)] (5), two-electron reduced Keggin clusters as hexadentate linkages are inserted in the rhomboid-like tunnels of the Ag-btp framework and connect with the framework via six Ag-O bonds to achieve 3D motifs, which are new and rare examples of heteropoly blue based hybrid compounds. The successful synthesis of the five high-dimensional structures may provide a feasible route for us to approach 3D polyoxometalate-based hybrids by using substituted Keggin anions and heteropoly blues with high charge density. Furthermore, photocatalytic experiments indicate that both 1 and 4 have good activities for photocatalytic degradation of RhB under UV irradiation. The luminescent properties of compounds 1-5 in the solid state were also investigated.

Polynuclear complexes of main group and transition metals with polyaminopolycarboxylate and polyoxometalate.

Six supramolecular compounds constructed by main group and transition metals, polyoxotungstates (SiW(12)O(40)(4-)) and trans-N,N,N',N'-1,2-cyclohexanediaminotetraacetic acid (H(4)CyDTA), (NH(4))(3)[Ni(4)Na(H(2)O)(10)(CyDTA)(2)][SiW(12)O(40)]·10H(2)O (1) (NH(4))(2)[Cu(3)Na(2)(HCyDTA)(2)(H(2)O)(13)][SiW(12)O(40)]·5H(2)O (2), (NH(4))(2)[Zn(5)(CyDTA)(2)(H(2)O)(16)][SiW(12)O(40)]·8H(2)O (3), (NH(4))(4)[Cd(4)(CyDTA)(2)(H(2)O)(8)][SiW(12)O(40)]·6H(2)O (4), (NH(4))(4)[Sr(3)(HCyDTA)(2)(H(2)O)(14)][SiW(12)O(40)]·2H(2)O (5) and [Ca(4)(H(2)CyDTA)(2)(H(2)O)(22)][SiW(12)O(40)]·8H(2)O (6), were synthesized in aqueous solution and characterized by IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction techniques. Single-crystal structure analyses indicate they are constructed by the complexes with different nuclearity and polyoxometalates. In the sequence of Ni, Cu, Zn the nuclearity of the homometallic complex units increases from 2 to 5. Cadmium ions gives a tetranuclear complex with a compact structure. In 5 and 6 the main group metal ions and CyDTA form polymeric chains. CyDTA exhibits rather different coordination patterns to main group metal ions and transition metal ions due to their ionic radii and electronic configuration. The complex units and polyoxometalates arrange in different patterns due to the different shapes of the complex units. The compounds exhibit different thermal decomposition processes and the formation of compounds 3 and 4 quenches ligand-centered emissions and gives a ligand-to-metal emission. The study on various temperature susceptibilities of 1 and 2 shows that there is an antiferromagnetic coupling in the two compounds but coupling patterns are different.

A sodalite-type porous metal-organic framework with polyoxometalate templates: adsorption and decomposition of dimethyl methylphosphonate.

A sodalite-type porous metal-organic framework with polyoxometalate templates, H(3)[(Cu(4)Cl)(3)(BTC)(8)](2)[PW(12)O(40)]·(C(4)H(12)N)(6)·3H(2)O (NENU-11; BTC = 1,3,5-benzenetricarboxylate), was obtained by a hydrothermal reaction. As a reasonable candidate for eliminating nerve gas, NENU-11 displays good adsorption behavior for dimethyl methylphosphonate (15.5 molecules per formula unit). In virtue of the catalytic activity of polyoxometalate guests, this nerve gas mimic could be facilely decomposed by a hydrolysis reaction.

Tailoring microstructures of isopolymolybdates: regular tuning of the ligand spacer length and metal coordination preferences.

Four new isopolymolybdate compounds based on two kinds of isomers, [Cu(I)(2)bte][a-Mo(3)O(10)] (1), [Cu(I)(2)btp][b-Mo(3)O(10)].H(2)O (2), [Cu(II)(bte)(1.5)(H(2)O)][gamma-Mo(8)O(26)](0.5) (3) and [Cu(II)(btp)(2)(H(2)O)][beta-Mo(8)O(26)](0.5).2H(2)O (4) [bte = 1,2-bis(1,2,4-triazol-1-yl)ethane, btp = 1,3-bis(1,2,4-triazol-1-yl)propane], were obtained under hydrothermal conditions, indicating that isopolymolybdate clusters can be tailored by regular tuning of the spacer length of the flexible ligands and the metal coordination preferences. In compound 1, wave-like a-[Mo(3)O(10)](2-) chains intersect with [Cu(I)(2)bte](2+) chains by sharing Cu(I) cations, forming a 3D framework. Compound 2, with a similar 3D structure but different ligand (btp) to 1, is based on linear b-[Mo(3)O(10)](2-) chains. In compound 3, gamma-[Mo(8)O(26)](4-) chains insert into the rectangular windows of parallel [Cu(II)(2)bte](4+) sheets and connect them via four Cu(II)-O bonds, leading to a 3D framework. Compound 4 is an unusual 2D-->3D polycatenated array of a [Cu(II)(btp)(2)(H(2)O)][beta-Mo(8)O(26)] pillar-layered framework. The thermal stability and luminescent properties of compounds 1-4 were investigated in the solid state.

[Experimental study on glucose solution by laser-induced breakdown spectroscopy].

The glucose solution was broken down by focusing the 1.064 microm beam of a Nd : YAG laser, and the plasma was produced. The spectral signals were detected by an experimental setup including spectrograph and ICCD. The spectral line at 247.86 nm was identified as the characteristic of glucose by contrasting the spectra of glucose solution and pure water. Comparing the spectral intensities of three kinds of glucose solution with different concentrations (3%, 6% and 9%), the experimental result showed that the bigger the concentration, the stronger the spectral intensity,and the characteristic spectral intensities with the three concentrations present the trend of logarithm increase. At the same concentration, the time evolution curve of the characteristic spectra was obtained by changing the delay time of ICCD. It is concluded that the intensity of the characteristic spectra first increases and then decreases with the delay time. With the glucose solution concentration altering, the decay time of the characteristic spectra is nearly fixed, meaning that the decay time is independent of the concentration. The decay time of the characteristic spectra is about 300 ns. Furthermore, it was found that the characteristic spectral intensities of glucose solution with different concentrations reach the maximum at the same delay time.

Erratum: An ionic organic-inorganic hybrid: tetra-kis[bis-(1,10-phenanthroline)copper(I)] dodeca-tungstophosphate(V). Corrigendum.

The chemical name in the title of the paper by Meng, Liu & Chen [Acta Cryst. (2008), E64, m106] is corrected.[This corrects the article DOI: 10.1107/S1600536807062903.].

Tris[tris-(1,10-phenanthroline-κN,N')iron(II)] dodeca-tungstoferrate dihydrate.

The title compound, [Fe(C(12)H(8)N(2))(3)](3)[FeW(12)O(40)]·2H(2)O, was prepared under hydro-thermal conditions. The discrete Keggin-type [FeW(12)O(40)](6-) heteropolyoxoanion has threefold symmetry, with the Fe(II) atom located on the threefold rotation axis. The central FeO(4) tetra-hedron in the anion shares its O atoms with four W(3)O(13) trinuclear units, each of which is made up of three edge-shared WO(6) octa-hedral units. The Fe(II) atom in the complex cation, viz [Fe(phen)(3)](2+) (phen is 1,10-phen-anthroline), shows a slightly distorted octa-hedral geometry defined by six N atoms from three phen ligands. The polyoxoanions pack together with the cations, with the disordered water mol-ecules located in voids; the site occupancy factor for each water O atom is 0.33.

An ionic organic-inorganic hybrid: tetra-kis[bis-(1,10-phenanthroline)copper(I)] dodeca-tungstophosphate(V).

Single crystals of the title polyoxometallate-based organic-inorganic hybrid, [Cu(C(12)H(8)N(2))(2)](4)[SiW(12)O(40)], were grown under hydro-thermal conditions. The discrete [SiW(12)O(40)](4-) anions are of the Keggin type and are packed in a slightly distorted ortho-rhom-bic F-centred mode, with the complex [Cu(I)(phen)(2)](+) cations (phen is 1,10-phenanthroline) located in the voids of this arrangement. The four independent Cu(I) cations are situated in the centres of more or less distorted tetra-hedra made up of N atoms from the phen ligands. The anions and cations are linked together via weak hydrogen-bonding inter-actions, forming an extended three-dimensional network. Additional stabilization is achieved via π-π inter-actions between different phen mol-ecules of adjacent [Cu(I)(phen)(2)](+) cations with shortest distances between 3.416 and 3.499 Å.

A novel copper(II) coordination polymer with 2,2'-bipyridyl-3,3'-dicarboxylic acid.

A novel copper(II) coordination polymer, poly[[[aquacopper(II)]-mu3-2,2'-bipyridyl-3,3'-dicarboxylato-kappa4N,N':O:O'] dihydrate], {[Cu(C12H6N2O4)(H2O)].2H2O}n, was obtained by the reaction of CuCl2.2H2O and 2,2'-bipyridyl-3,3'-dicarboxylic acid (H2L) in water. In the molecule, each Cu(II) atom is five-coordinated and lies at the centre of a square-pyramidal basal plane, bridged by three L ligands to form a two-dimensional (4,4)-network. Each L moiety acts as a bridging tetradentate ligand, coordinating to three Cu(II) atoms through its two aromatic N atoms and two O atoms of the two carboxyl groups. The two-dimensional square-grid sheets superimpose in an off-set fashion through the inorganic water layer.