Self-assembly of a unique triangle-like tungstovanadate containing pentagonal {(WO)W(SnR)} cluster.

In aqueous solution, a novel triangle-like tungstovanadate estertin derivative KH[(WO(HO)){(SnCHCHCOO)(VW/VO)}{{(SnCHCHCOO)(μ-OH)}(SnCHCHCOO)(VWO)}]·31HO ((SnR)8-V3W35, R = CHCHCOO) was assembled by a conventional synthetic method. (SnR)8-V3W35 is composed of one [VWO] ({VW}) and two [VWO] ({VW}) units connected by eight [Sn(CH)COO] groups and a {WO} cluster. Interestingly, there exists a pentagonal bipyramid WO polyhedral center surrounded by two SnCO and three WO octahedra, forming a pentagonal {(WO)W(SnR)} cluster in this polyoxometalate (POM), which is also the first example of a pentagonal structure formed by transition metals (TMs) and main group organometals in the POM family.

Enhanced Corrosion Resistance of Carbon Steel in Hydrochloric Acid Solution by Polyoxometalate-Estertin Derivatives.

The development of acid-resistant and efficient corrosion inhibitors is of great significance for metal protection in many industrial processes. In this work, eight cases of sandwich-type polyoxometalate (POM)-based inorganic-organic hybrids, namely, carboxyethyltin and transition metal (TM) cofunctionalized tungstoantimonates and tungstobismuthates, formulated as Na K [(SnR)(TM(HO))(B-β-SbWO)]·HO and Na K [(SnR)(TM(HO))(B-β-BiWO)]·HO (abbreviated as and ; TM = Mn, Co, Ni, and Zn; = 18, 24, 24, and 22; = 30, 25, 20, and 21; SnR = Sn(CHCHCOO)) are first used as green corrosion inhibitors for 20 carbon steel in 0.5-2.

A POM-based copper-coordination polymer crystal material for phenolic compound degradation by immobilizing horseradish peroxidase.

A new polyoxometalate (POM)-based organic-inorganic hybrid Cu-coordination polymer, namely {((Cu(bipy))(-PhPO)Cu(bipy))H(PCuWO)·3HO} (denoted as compound 1, bipy = 2,2'-bipyridine, PhPO = phenylphosphonate), was self-assembled hydrothermally. Single-crystal X-ray diffraction (SC-XRD) analysis shows that two unique types of 1D chains are present in compound 1, Cu(II)-organophosphine and organonitrogen complex cation ([((Cu(bipy))(-PhPO)Cu(bipy))]) chains and Cu-monosubstituted Keggin-type polyoxoanion ([PCuWO]) chains, forming a hetero-POM. Crystalline compound 1 as a new enzyme immobilization support exhibited a high horseradish peroxidase (HRP) loading capacity (268 mg g).

Two new estertin modified tungstosilicates: synthesis, catalytic activity and photoelectrochemical property.

Two new tungstosilicates (C(NH))KNaH[Sn(CHCHCOOCH)Co(HO)SiWO]·10HO (SiW-Co-SnRCOOCH) and (C(NH))KNaH[Sn(CHCHCOOCH)Mn(HO)SiWO]·13HO (SiW-Mn-SnRCOOCH) modified by organometal (OM) and transition metal (TM) ions were obtained, and they were self-assembled from mono-TM-containing (TM = Co, Mn) γ-[SiWO] (γ-SiW)-based dimeric tungstosilicate and estertin ClSnCHCHCOOCH in an acetate buffer solution, respectively. Their structures were determined with a series of physico-chemical and spectroscopic methods including X-ray crystallography, XRPD, etc. The estertin functional position in the tungstosilicate skeleton was analyzed by theoretical calculations using density functional theory (DFT).

Carboxyethyltin and transition metal co-functionalized tungstoantimonates composited with polypyrrole for enhanced electrocatalytic methanol oxidation.

Carboxyethyltin and first-row transition metals (TMs) were firstly introduced into trivacant Keggin-type tungstoantimonate in an aqueous solution, leading to the formation of four crystalline organic-inorganic hybrid sandwich-type polyoxometalates (POMs), formulated as Na10-x-yKyHx[((TM)(H2O)3)2(Sn(CH2)2COO)2(SbW9O33)2]·nH2O (SbW9-TM-SnR, TM = Mn, Co, Ni, Zn; x = 1, 1, 0, 0; y = 0, 5, 5, 2; n = 18, 24, 24, 22, respectively). SbW9-TM-SnR exhibit high catalytic ability for the oxidation of cyclohexanol. Meanwhile, SbW9-TM-SnR were composited with polypyrrole (PPy) through an electropolymerization process, forming PPy-SbW9-TM-SnR, on which platinum (Pt) was further electro-deposited to prepare PPy-SbW9-TM-SnR/Pt for electrocatalytic methanol (CH3OH) oxidation in acid solution.

A new hexamolybdate-based copper-2,2'-biimidazole coordination polymer serving as an acid catalyst and support for enzyme immobilization.

The hydrothermal reaction of (NH)[CoMoOH]·7HO (CoMo), CuCl·2HO and 2,2'-biimidazole (Hbiim) led to the formation of a new coordination polymer, namely poly[diaquabis(2,2'-biimidazole)hexa-μ-oxo-octa-μ-oxo-hexaoxodicopper(II)hexamolybdate(VI)], [CuMoO(CHN)(HO)] (Cu-MoO), at pH 2-3. It is obvious that in the formation of crystalline Cu-MoO, the original Anderson-type skeleton of heteropolymolybdate CoMo was broken and the new isopolyhexamolybdate MoO unit was assembled. In Cu-MoO, one MoO unit connects four [Cu(Hbiim)(HO)] ions in a pentacoordinate mode via four terminal O atoms, resulting in a tetra-supported structure, and each Cu ion is shared by two adjacent MoO units.

Three new Strandberg-type phenylphosphomolybdate supports for immobilizing horseradish peroxidase and their catalytic oxidation performances.

Three organic-inorganic hybrids containing Strandberg-type phenylphosphomolybdate anion [(C6H5PO3)2Mo5O15]4- with phenylphosphonate (PhP) centers, transition metal (TM) ions and 2,2'-biimidazole (H2biim) ligand, formulated as [(TM(H2biim)2)2(C6H5PO3)2Mo5O15]·H2O (TM = Co and Cu, abbreviated as Co-(PhP)2Mo5 and Cu-(PhP)2Mo5, respectively) and ([Ni(H2biim)3])2[(C6H5PO3)2Mo5O15]·2H2O (abbreviated as Ni-(PhP)2Mo5), were self-assembled by simple hydrothermal methods and were systematically characterized through single-crystal X-ray diffraction and other physicochemical and spectroscopic methods, which demonstrated that TM-H2biim complexes were firstly introduced into Strandberg-type organophosphomolybdate skeletons. Selecting the oxidation of cyclohexanol to cyclohexanone as a model reaction, using H2O2 as an oxidant, the catalytic oxidation activities of the Strandberg-type compounds were firstly evaluated. More importantly, these TM-(PhP)2Mo5 (TM = Co, Cu, Ni) compounds were employed to immobilize horseradish peroxidase (HRP), and showed high adsorption capacities for HRP.

Two New Preyssler-Type Polyoxometalate-Based Coordination Polymers and Their Application in Horseradish Peroxidase Immobilization.

Enzyme immobilization is of increasing importance for biocatalysis, for which good supports are critical. Herein, two new Preyssler-type polyoxometalate (POM)-based coordination polymers, namely, {[Cu(H biim) ][{Cu(H biim) (μ-H O)} Cu(H biim)(H O) ]H[({Cu(H biim)(H O) } ) ((μ-C HN Cl ){Cu(H biim)} ){Z(H O)P W O }]⋅x H O} (1: Z=Na, x=9; 2: Z=Ag, x=10; H biim=2,2'-biimidazole) were designed and synthesized. Compounds 1 and 2 exhibit the same skeletons, which contain multiple Cu complex fragments and penta-supported {ZP W } (Z=Na, Ag) clusters.

Two New Armtype Polyoxometalates Grafted on Titanium Dioxide Films: Towards Enhanced Photoelectrochemical Performance.

Two new carboxyethyltin-functionalized polyoxometalates (POMs) were successfully obtained and confirmed with physicochemical and spectroscopic methods including X-ray crystallography. The lowest unoccupied molecular orbitals of both compounds are higher in energy than that of TiO2 , and the optical band gaps of these compounds are smaller than that of TiO2 . Grafting them onto a TiO2 film created two kinds of novel photoanode materials that showed significantly enhanced photovoltaic and photocurrent responses, as well as improved photoelectrooxidation activities for methanol relative to that shown by a single TiO2 film.

Controllable assembly, characterization and catalytic properties of a new Strandberg-type organophosphotungstate.

Using phenylphosphonic acid, simple tungstate and copper(ii) compounds as starting materials, an organic-inorganic hybrid Strandberg-type organophosphotungstate, {[(Cu(H2O)(μ-bipy))2(C6H5PO3)2W5O15]}n (bipy = 4,4'-bipyridyl) (1), was assembled successfully under hydrothermal conditions and characterized by physico-chemical and spectroscopic methods. Compound 1 represents the first example of a transition metal complex modified organophosphotungstate cluster. In the crystal structure of compound 1, the polymeric 1-D {Cu-bipy}n chains are interconnected by [(C6H5PO3)2W5O15](4-) (abbreviated as {(C6H5P)2W5}) units into a 3-D framework.

Enhanced Visible Photovoltaic Response of TiO₂ Thin Film with an All-Inorganic Donor-Acceptor Type Polyoxometalate.

In the field of material chemistry, it is of great significance to develop abundant and sustainable materials for solar energy harvesting and management. Herein, after evaluating the energy band characteristics of 13 kinds of polyoxometalates (POMs), the trisubstituted POM compound K6H4[α-SiW9O37Co3(H2O)3]·17H2O (SiW9Co3) was first studied due to its relatively smaller band gap (2.23 eV) and higher lowest unoccupied molecular orbital (LUMO) level (-0.

An open chain carboxyethyltin functionalized sandwich-type tungstophosphate based on a trivacant Dawson subunit: synthesis, characterization and properties.

A Dawson sandwich-type polyoxometalate {C(NH2)3}12H4[αββα-{(Sn(C3H4O2))2Mn2(P2W15O56)2}]·22H2O (abbreviated as SnR-Mn-P2W15), functionalized by open chain carboxyethyltin groups, was first prepared in aqueous solution under conventional reaction conditions, and then structurally characterized by physicochemical and spectroscopic methods. Single crystal X-ray diffraction analysis revealed that two Mn(2+) cations and two [Sn(CH2CH2COO)](2+) groups are located in the internal and external positions in the so-called equatorial region of SnR-Mn-P2W15, respectively. Intriguingly, two exposed carboxyl groups act as stretching-arm brackets, which provide a favorable structure for potential further functionalization.

Two Strandberg-type organophosphomolybdates: synthesis, crystal structures and catalytic properties.

Two novel Strandberg-type organophosphomolybdate hybrid compounds [(Cu(H2O))2(μ-bipy)2(C6H5PO3)2Mo5O15]n (1) and [(Cu(H2O)2)2(μ-bipy)(C6H5PO3)2Mo5O15]n (2) (bipy = 4,4'-bipyridyl) were prepared under mild hydrothermal conditions and structurally characterized by physico-chemical and spectroscopic methods. Single crystal X-ray diffraction analysis reveals that compounds 1 and 2 are polyoxometalate-based Cu-coordination polymers with a three-dimensional framework. In 1, the Cu(2+) ions not only link [(C6H5PO3)2Mo5O15](4-) (abbreviated as {(C6H5P)2Mo5}) polyanions, but also act as connectors of bipy ligands to produce two symmetrical 1-D chains, all 1-D chains are further held together by polyanions to generate a 3-D network.

Two carboxyethyltin functionalized polyoxometalates for assembly on carbon nanotubes as efficient counter electrode materials in dye-sensitized solar cells.

Two novel open-chain carboxyethyltin decorated sandwich-type germanotungstates have been successfully synthesized. They could markedly increase the electrocatalytic activity of single-walled carbon nanotubes toward triiodide reduction when assembled into composite electrodes, which have shown a conversion efficiency of 6.32% that is comparable to that of Pt electrodes (6.

Three molybdophosphates based on Strandberg-type anions and Zn(II)-H2biim/H(2)O subunits: syntheses, structures and catalytic properties.

Three new inorganic-organic hybrid compounds based on Strandberg-type anions and Zn(ii)-H2biim/H2O subunits, namely {H4(H2biim)3}[Zn(H2biim)(H3biim)(H2O)(HP2Mo5O23)]2·3H2O (1), {H9(H2biim)7}[(μ-biim){(Zn(H2O)2)0.5(HP2Mo5O23)}2]·7H2O (2) and {H7(H2biim)7}[Zn(H2biim)(H2O)2(HP2Mo5O23)][H2P2Mo5O23]·8H2O (3) (H2biim = 2,2'-biimidazole), have been synthesized in aqueous solutions and characterized. They were also used as efficient and reusable catalysts for the protection of carbonyl compounds.

New tetra(organotin)-decorated boat-like polyoxometalate.

The reaction of Cl(3)Sn(CH(2))(2)COOCH(3), [H(2)P(2)W(12)O(48)](12-) and WO(4)(2-) in acetate buffer solution led to the hydrolysis of estertin into a carboxyethyltin group and the assembly of a new tetra(organotin)-decorated boat-like polyoxometalate.

Effect of laminin tyrosine-isoleucine-glycine-serine-arginine peptide on the growth of human prostate cancer (PC-3) cells in vitro.

The laminin tyrosine-isoleucine-glycine-serine-arginine (YIGSR) peptide, corresponding to the 929-933 sequence of beta1 chain, is known to inhibit tumor growth and metastasis. In the present study, we observed that YIGSR not only inhibited the growth and migration of prostate cancer cells in a dose-dependent manner but also decreased mitochondrial membrane potential, inhibited ATP synthesis and increased caspase-9 activity. Investigation into the interaction of YIGSR with 67LR, the receptor for laminin and polyphenol (-) epigallocatechin-3-gallate (EGCG) employing MVD (Molegro Virtual Docker, an integrated platform for predicting protein ligand interactions), revealed that the binding site of YIGSR was the same as that of EGCG that explains as to why YIGSR is able to inhibit the cytotoxicity of EGCG against PC-3 cells.

Epigallocatechin-3-gallate affects the growth of LNCaP cells via membrane fluidity and distribution of cellular zinc.

Objective: To evaluate effects of epigallocatechin-3-gallate (EGCG) on the viability, membrane properties, and zinc distribution, with and without the presence of Zn(2+), in human prostate carcinoma LNCaP cells.

Methods: We examined changes in cellular morphology and membrane fluidity of LNCaP cells, distribution of cellular zinc, and the incorporated portion of EGCG after treatments with EGCG, Zn(2+), and EGCG+Zn(2+).

Results: We observed an alteration in cellular morphology and a decrease in membrane fluidity of LNCaP cells after treatment with EGCG or Zn(2+).

[Growth inhibition of prostate cancer cells by epigallocatechin-3-gallate in the presence of Zn2+ in vitro].

In this paper, the cytotoxicity of EGCG against PC-3 prostate cancer cells and its molecular mechanism in the presence and absence of Zn2+ in vitro were investigated. The results showed that both EGCG and Zn2+ suppressed clonegenecity of PC-3 cells, and the suppression effect was enhanced in the coexist system of EGCG and Zn2+. MMP-9 is thought to play a significant role in cancer cell migration and invasion.

Investigations of the cytotoxicity of epigallocatechin-3-gallate against PC-3 cells in the presence of Cd2+ in vitro.

The epidemiological studies and recent data have provided convinced evidence that green tea and its major constituent epigallocatechin gallate (EGCG) might have the potential to lower the risk of cancers in humans. Metal ions, such as zinc and cadmium, which are necessary to our health, are important factors inducing many diseases including prostate cancer in the condition of absence or excess. EGCG can satisfactorily exhibit complex chemistry with metal ions because of multiple hydroxyl states, which in turn changes their bioactivities and metabolism pathways.

Free Zn(2+) enhances inhibitory effects of EGCG on the growth of PC-3 cells.

Epigallocatechin-3-gallate (EGCG), a major component of green tea, has both preventive and therapeutic beneficial actions in prostate cancer. In the present study, we compared the growth inhibitory effects and the antioxidant and ability to modify cell membrane permeation of zinc-EGCG complex and Zn2+/EGCG mixture on androgen-insensitive prostate cancer (PC-3) cells. It was noted that free Zn2+ enhanced the growth inhibitory effects of EGCG on PC-3 cells at 160 micromol/L concentration,whereas zinc-EGCG complex was ineffective.

2-(1,3-Dithian-2-yl-idene)-1-phenyl-butane-1,3-dione.

The title compound, C(13)H(12)O(2)S(2), belonging to the group of dioxoketene cyclic S,S-acetals, was prepared from the corresponding dione in high yield. In the structure, the C=O and C=C bonds are not coplanar, with O=C-C=C torsion angles of -36.8 (4) and -21.

Diaqua-bis(2,2'-biimidazole)cobalt(II) dichloride.

There are independent cations and four chloride anions in the crystal structure of the title complex, [Co(C(6)H(6)N(4))(2)(H(2)O)(2)]Cl(2). In each cation, the Co(II) cation is coordinated by four N atoms from two biimidazole and two O atoms of two water mol-ecules; one Co atom is at a position of site symmetry m, the other at a position of site symmetry 2/m. All Cl(-) ions and water mol-ecules are also located on the mirror plane.