New synergistic antibacterial mechanism of bulky mixed Ti/w hetero-polyoxometalates composed of multi lacunary Keggin structure with oxacillin against vancomycin intermediate-resistant Staphylococcus aureus.

Considering the lack of detailed research on the antibacterial mechanism of polyoxometalates, we examined the synergistic effect of novel bulky mixed Ti/W hetero-polyoxometalates (KH ［α-GeTiWO］・ 29HO; αTi4, KH ［α-GeTiWO］・16HO; αTi6, KH［α-GeTiWO］・39HO; αTi12, KH ［β-GeTiWO］・ 45HO; βTi6) with the antibiotic oxacillin against vancomycin intermediate-resistant Staphylococcus aureus (VISA) using fractional inhibitory concentration (FIC) index and growth curve in this study. All polyoxometalates used in this study showed remarkable synergistic effects with oxacillin. Its synergistic antibacterial mechanism was examined using reverse transcription PCR (RT-PCR) and penicillin binding protein-2' (PBP2') latex agglutination test.

"Mixed-Valence Decatungstates" Revisited: Crystal Structure and Aqueous Solution Chemistry of [WO] and an ESR Study on Electron Delocalization.

A [PrNH]/Na-mixed salt of unprotonated two-electron-reduced decatungstate, [PrNH][WO]·(NaCl)HO (), is isolated from the photolyte obtained by the UV photolysis of the NaWO·2HO/[PrNH]Cl aqueous solution at pH 6.5 and characterized in the solid state (X-ray diffraction and elemental analysis) and solution (UV-vis absorption and electrochemistry). [WO], as a paramagnetic contaminant in the crystallite of diamagnetic , shows only a broadened singlet-like electron spin resonance (ESR) line around = 1.

Molecular and electron-spin structures of a ring-shaped mixed-valence polyoxovanadate (IV, V) studied by (11)B and (23)Na solid-state NMR spectroscopy and DFT calculations.

(11)B and (23)Na solid-state nuclear magnetic resonance (NMR) spectra of ring-shaped paramagnetic crystals of H15[V7(IV)V5(V)B32O84Na4]·13H2O containing seven d(1) electrons from V(IV) were studied. Magic-angle-spinning (MAS) and multiple-quantum MAS NMR experiments were performed at moderate (9.4T) and ultrahigh magnetic fields (21.

Electron localization of polyoxomolybdates with ε-Keggin structure studied by solid-state 95Mo NMR and DFT calculation.

We report electron localization of polyoxomolybdates with ε-Keggin structure investigated by solid-state (95)Mo NMR and DFT calculation. The polyoxomolybdates studied are the basic ε-Keggin crystals of [Me3NH]6[H2Mo12O28(OH)12{MoO3}4] · 2H2O (1), the crystals suggested to have a disordered {ε-Mo12} core of [PMo12O36(OH)4{La(H2O)2.75Cl1.

Polyoxometalates active against tumors, viruses, and bacteria.

Polyoxometalates (PMs) as discrete metal-oxide cluster anions with high solubility in water and photochemically and electrochemically active property have a wide variety of structures not only in molecular size from sub-nano to sub-micrometers with a various combination of metals but also in symmetry and highly negative charge. One of the reasons for such a structural variety originates from their conformation change (due to the condensed aggregation and the structural assembly) which strongly depends on environmental parameters such as solution pH, concentration, and coexistent foreign inorganic and/or organic substances. In the course of the application of the physicochemical properties of such PMs to the medical fields, antitumoral, antiviral, and antibacterial activities have been developed for realization of a novel inorganic medicine which provides a biologically excellent activity never replaced by other approved medicines.

Molecular magnetism of M6 hexagon ring in D(3d) symmetric [(MCl)6(XW9O33)2](12-) (M = Cu(II) and Mn(II), X = Sb(III) and As(III)).

Ferromagnetic [n-BuNH(3)](12)[(CuCl)(6)(SbW(9)O(33))(2)]·6H(2)O (1) and antiferromagnetic [n-BuNH(3)](12)[(MnCl)(6)(AsW(9)O(33))(2)]·6H(2)O (4) have been synthesized and structurally and magnetically characterized. Two complexes are structural analogues of [n-BuNH(3)](12)[(CuCl)(6)(AsW(9)O(33))(2)]·6H(2)O (2) and [n-BuNH(3)](12)[(MnCl)(6)(SbW(9)O(33))(2)]·6H(2)O (3) with their ferromagnetic interactions, first reported by us in 2006. (1) When variable temperature (T) direct current (dc) magnetic susceptibility (χ(M)) data are analyzed with the isotropic exchange Hamiltonian for the magnetic exchange interactions, χ(M)T vs T curves fitted by a full matrix diagonalization (for 1) and by the Kambe vector coupling method/Van Vleck's approximation (for 4) yield J = +29.

{Mo96La8} eggshell ring and self-assembly to {Mo132} Keplerate through Mo-blue intermediate, involved in UV-photolysis of [Mo7O24](6-)/carboxylic acid system at pH 4.

The prolonged UV-photolysis of aqueous solutions containing [Mo(7)O(24)](6-) and C(2)H(5)CO(2)H (as electron donor) at pH 3.9-4.1 generates the carboxylate-coordinated {Mo(132)} Keplerate (1a) isolated as a formamidinium/ammonium-mixed salt, [HC(NH(2))(2)](26)(NH(4))(28)[Mo(V)(60)Mo(VI)(72)O(372)(H(2)O)(48)(C(2)H(5)CO(2))(36)((i)C(3)H(7)CO(2))(6)]·16H(2)O (1), through the Mo-blue intermediate (2).

Dual-emissive photoluminescent Langmuir-Blodgett films of decatungstoeuropate and an amphiphilic iridium complex.

Langmuir monolayers and Langmuir-Blodgett (LB) films of the decatungstoeuropate [Eu(W(5)O(18))(2)](9-) (EuW(10)) and the amphiphilic Ir complex 1 have been successfully fabricated by using the adsorption properties of the EuW(10) polyanion dissolved in the aqueous subphase onto a positively charged 1 monolayer at the air-water interface. The compression isotherms and Brewster angle microscopy (BAM) of monolayers of 1 on pure water (1 monolayer) and on a subphase containing 10(-6) M EuW(10) and 10(-3) M NaCl (1/EuW(10) monolayer) have been studied. Infrared and UV-vis spectroscopy of the transferred LB films indicate that EuW(10) and 1 molecules are incorporated within these LB films.

Polyoxometalates as effective inhibitors for sialyl- and sulfotransferases.

Sialylated and/or sulfated carbohydrate chains in glycoproteins and glycolipids play important roles in infection by microorganisms and diseases including cancer. Inhibitors of sialyl/sulfotransferases, responsible for the biosynthesis of these carbohydrate chains, could be medical agents against such infections and diseases. Polyoxometalates (PMs) are inorganic polyanionic molecules that have been shown to exhibit activity against tumors and infectious microorganisms; however, the effects of PMs on carbohydrate biosynthesis have never been investigated.

Structure and magnetism of [n-BuNH3]12[Cu4(GeW9O34)2].14H2O sandwiching a rhomblike Cu4(8+) tetragon through alpha-Keggin linkage.

A sandwich-type polyoxometalate, [Cu(4)(GeW(9)O(34))(2)](12-) (1a), in which two B-alpha-[GeW(9)O(34)](12-) ligands sandwich a rhomblike Cu(4)(8+) tetragon through alpha-Kappaeggin linkage, is first isolated as a [n-BuNH(3)](+) salt, [n-BuNH(3)](12)[Cu(4)(GeW(9)O(34))(2)].14H(2)O (1). A Cu(4)O(14) cluster for the rhomblike Cu(4)(8+) tetragon in 1a with C(2h) local symmetry consists of two Jahn-Teller (JT) distorted CuO(6) octahedra (at internal sites) with a short diagonal Cu(int).

Enhancement effect of polyoxometalates on NGF-induced neurite-outgrowth of PC12 cells.

Nerve growth factor (NGF)-induced neurite-outgrowth of PC12 cells was enhanced by polyoxometalates such as Na9[SbW(9)O(33)].19.5H(2)O (SbW(9)) and (NH(3)Pr(i))6[Mo(7)O(24)].

Langmuir-Blodgett films of a Mo-blue nanoring [Mo(142)O(429)H(10)(H(2)O)(49)(CH(3)CO(2))(5)(CH(3)CH(2)CO(2))](30)(-) (Mo(142)) by the semiamphiphilic method.

Langmuir monolayers and LB films of the ring-shaped mixed-valence polyoxomolybdate [Mo142O429H10(H2O)49(CH3CO2)5(CH3CH2CO2)](30-) (Mo142) dissolved in the aqueous subphase have been successfully fabricated by using the adsorption properties of a DODA monolayer. Infrared and ultraviolet-visible spectroscopy of the LB films indicates that Mo142 and DODA molecules are incorporated within these LB films. X-ray reflectivity experiments indicate that the LB films exhibit a well-defined lamellar structure formed by bilayers of DODA molecules alternating with monolayers of Mo142.

Ferromagnetic exchange interactions for Cu6(12+) and Mn6(12+) hexagons sandwiched by two B-alpha-[XW9O33]9- (X = As(III) and Sb(III)) ligands in D3d-symmetric polyoxotungstates.

Two novel Cu6 and Mn6 hexagon sandwiched polyoxometalates, [(CuCl)6(AsW9O33)2]12- (1a) and [(MnCl)6(SbW9O33)2]12- (2a), have been synthesized and characterized by X-ray single-crystal analysis and magnetic measurements. These complexes are D3d symmetric and were isolated as [n-BuNH3]+ salts from aqueous solutions: (n-BuNH3)12[(CuCl)6(AsW9O33)2].6H2O (1), rhombohedral, R, a = 20.

Anti-RNA virus activity of polyoxometalates.

The anti-RNA virus activity of polyoxometalates (POM) is reviewed, with a special emphasis on the anti-respiratory virus activities. There are many causative agents of acute viral respiratory infections; and it is rather difficult to identify the relevant agent in a given case by rapid clinical means. During acute progress of infection before the definitive diagnosis is obtained physicians need to prescribe certain broad spectrum anti-viral drugs.

Prevention of the interaction between HVEM, herpes virus entry mediator, and gD, HSV envelope protein, by a Keggin polyoxotungstate, PM-19.

One of the Keggin-type heteropolyoxotungstates (K7[PTi2W10O40]6H2O:PM-19) is a potent inhibitor of the replication of herpes simplex virus (HSV) both standard strain 169 and the thymidine kinase-defective strain YS-4C-1 in vitro and in vivo. HSV envelope protein, gD, is necessary for virus entry into the cells. Some cellular molecules, such as HVEM, were reported to act as cofactors during the viral entry step.

Enhancement of antibacterial activity of beta-lactam antibiotics by [P2W18O62]6-, [SiMo12O40]4-, and [PTi2W10O40]7- against methicillin-resistant and vancomycin-resistant Staphylococcus aureus.

The enhancement of antibacterial activity of beta-lactam antibiotics by polyoxometalates against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) was investigated by using K6[P2W18O62] . 14H2O (P2W18), K4[SiMo12O40] .

Regular two-dimensional molecular array of photoluminescent Anderson-type polyoxometalate constructed by Langmuir-Blodgett technique.

A regular two-dimensional photoluminescent array of Anderson-type polyoxometalates (POMs) was constructed as built-up Langmuir-Blodgett (LB) films. LB films of hexatungstoantimonate (SbW(6)) and -manganate (MnW(6)) were successfully fabricated by using dimethyldioctadecylammonium (DODA) as cationic partner, while hexamolybdochromate (CrMo(6)) was unsuccessful. Specular X-ray reflectivity (SXR) and grazing incidence X-ray diffraction (GIXD) measurements revealed that both SbW(6)/DODA and MnW(6)/DODA LB films exhibited well-ordered layers consisting of periodic arrangement of the planar-structured Anderson-type molecules.

31P NMR and isothermal titration calorimetry studies on polyoxomolybdates-catalyzed hydrolysis of ATP.

ATP hydrolysis in the presence of polyoxomolybdates at pH levels of 6, 4, and 2 has been investigated with a help of high pressure liquid chromatography (HPLC) analyses, 31P- and 1H NMR measurements, and isothermal titration calorimetry (ITC). The polyoxomolybdates-induced ATP-hydrolysis proceeded satisfactorily in pH < 6 media at 20 degrees C with an optimum pH level of 4, while it was significantly depressed at low temperature of < or = 5 degrees C. At pH levels of 6 and 4, ADP was a main product, and the involvement of [(PO4)2Mo5O15](6-)-like ATP-molybdate complex as an intermediate was implied.

Photoreductive self-assembly from [Mo7O24]6- to carboxylates-coordinated {Mo142} Mo-blue nanoring in the presence of carboxylic acids.

The primary steps of the photoredox reaction between [Mo7O24]6- and carboxylic acid electron (and proton) donors in aqueous solutions are investigated by the chemically induced dynamic electron spin polarization (CIDEP) spectroscopy. The excitation of the O-->Mo ligand-to-metal charge-transfer (LMCT) bands of [Mo7O24]6- in the presence of CH3CO2H induces the emissive electron spin polarization (ESP) of *CH2CO2 and *CH3 radicals with an accompanying formation of the one-electron reduced species [Mo7O23(OH)]6-, which is demonstrated by the triplet mechanism involving the O --> Mo LMCT triplet states. The prolonged photolysis of the solution containing [Mo7O24]6- and CH3CO2H at pH = 3.

Antibacterial activity of highly negative charged polyoxotungstates, K27[KAs4W40O140] and K18[KSb9W21O86], and Keggin-structural polyoxotungstates against Helicobacter pylori.

The antibacterial activity of polyoxometalates (PMs) against Helicobacter pylori was investigated based on determinations of minimum inhibitory concentration (MIC) and fractional inhibitory concentration (FIC), time-killing of the bacteria, bacterial morphology and PM-uptake into the bacteria cell. The result of MIC values revealed that, of 13 PMs used in this study, highly negative-charged polyoxotungstates, such as K27[KAs4W40O140] and K18[KSb9W21O86], and Keggin-structural polyoxotungstates exhibited a potent antibacterial activity with the MIC values of less than 256 microg/ml. The former was the most active, and superior to metronidazole (MTZ) against MTZ-susceptible and resistant strains and also to clarithromycin (CLR) against CLR-resistant strains.

Current status of anti-SARS agents.

Severe acute respiratory syndrome (SARS) is a disease that has newly emerged in the 21st century, and is both severe and highly contagious. SARS first surfaced in late 2002 and spread within a few months from its origin in Guandong province, China, to more than 30 countries (World Health Organization, 2003). In this review, several antiviral substances shown to be active in vitro will be introduced and summarized in the order of the virus' replication steps; that is, binding to cellular receptor, fusion and entry to the cells, viral RNA replication and transcription, protein processing and so on.

Spin-frustrated (VO)36+-triangle-sandwiching octadecatungstates as a new class of molecular magnets.

Spin-frustrated polyoxometalates, K(11)H[(VO)(3)(SbW(9)O(33))(2)].27H(2)O (1) and K(12)[(VO)(3)(BiW(9)O(33))(2)].29H(2)O (2), containing approximately equilateral and isosceles (VO)(3)(6+)-triangles (V(IV).

Broad spectrum anti-RNA virus activities of titanium and vanadium substituted polyoxotungstates.

Seven polyoxotungstates substituted with vanadium or titanium atoms were examined for their activity against Flaviviridae (Dengue fever virus, DFV), Orthomyxoviridae (influenza virus type A, fluV-A), Paramyxoviridae (respiratory syncytial virus, RSV, parainfluenza virus type 2, PfluV-2 and canine distemper virus, CDV) and Lentiviridae (human immunodeficiency virus type 1, HIV-1) families. Among the seven polyoxotungstates examined, PM-43 [K(5)[SiVW(11)O(40)]], PM-47 [K(7)[BVW(11)O(40)]], and PM-1001 [K(10)Na(VO)(3)(SbW(9)O(33))(2)]26H(2)O contained vanadium. PM-1002 had the same core structure of (VO)(3)(SbW(9)O(33))(2) as PM-1001; however, three V atoms of PM-1001 consisted of two V(IV) and one V(V) and those of PM-1002 consisted of three V(IV).

Mechanism of the protective effect of heteropolyoxotungstate against herpes simplex virus type 2.

The effects of heteropolyoxotungstate (K(7)[PTi(2)W(10)O(40)]. 6H(2)O; PM-19) on the replication of herpes simplex virus type 2 (HSV-2) were examined using a semiquantitative polymerase chain reaction of intracellular viral DNA established by us and also other methods. Vero cells were infected with HSV-2 strains: either the standard strain 169, or the acyclovir-resistant strain YS-4C-1.