Michael T. Pope

Polyoxometalates : from platonic solids to anti-retroviral activity

Polyoxometalates: A Class of Compounds with Remarkable Topology.- A: Formation and Structure.- Equilibria of Polyoxometalates in Aqueous Solution.- Synthesis and Structural Chemistry of Novel Heteropolymolybdates and -tungstates.- Progress in Polytungstophosphate and -arsenate(V) Chemistry.- Crystal Structure Studies of Isopoly and Heteropoly Oxometalates. Structure of the Paradodecatungstate Molecule and Its Environment in Crystals.- Polyoxoanion-Supported Organometallic Complexes.- New Aspects of Non-Aqueous Polyoxometalate Chemistry.- Functionalization of Polyoxomolybdates: the Example of Nitrosyl Derivatives.- Polyoxoalkoxy Molybdenum and Vanadium Clusters.- Polyoxovanadates with Organic Ligands.- B: Spectroscopy and Magnetochemistry.- New Aspects of NMR Spectroscopy of Polyoxometalates.- Polyoxotungstates with Lone-Pair Assembling Atoms: Part 2: 183W NMR Structural Study of the Inorganic Cryptates [MAs4W40O140](28-n)- and [MSb9W21O86](19-n)-(Mn+ = Alkaline or Alkaline Earth Cation).- Blue Electron Distributions in Diamagnetic Reduced Heteropoly Tungstates. Insights Concerning Conduction Pathways and Spin Coupling Patterns. 183W NMR Chemical Shift Calculations.- Interactions between Delocalized and Localized Electrons in Heteropoly Blues Containing Paramagnetic Transition Metals. Magnetic Susceptibility and NMR Studies.- Polyoxovanadates: The Missing Link between Simple Paramagnets and Bulk Magnets?.- Molecular Magnetic Materials from Polyoxometalates.- The Use of Polyoxometalates in Charge Transfer Salts.- C: Applications-Catalysis and Biology.- Catalytic Chemistry of Solid Polyoxometalates and Their Industrial Applications.- Polyoxoanions in Homogeneous Catalysis: Polyoxoanion-Supported, Atomically-Dispersed Iridium, [(l,5-COD)Ir-P2W15Nb3O62]8-.- Palladium and Phosphomolybdovanadate Catalyzed Olefin Oxidation to Carbonyls.- Mixed Addenda Phosphomolybdovanadates as Catalysts for Oxidations Dioxygen and Hydrogen Peroxide.- Role of Vanadium in Oxidation Catalysis by Heteropolyanions.- Photocatalytic Processes by Polyoxometalates. Splitting of Water. The Role of Dioxygen.- Polyoxometalates for Molecular Devices: Antitumor Activity and Luminescence.- Polyoxometalates in Catalytic Selective Homogeneous Oxygenation and Anti-HIV Chemotherapy.- Of Therapy, Toxicity and Tungstates: The Anti-Retroviral Pharmacology of Polyoxometalates.- Polyoxometalates in AIDS Therapy.- Interactions of Oxovanadates and Selected Oxomolybdates with Proteins.

Polyoxometalate chemistry : from topology via self-assembly to applications

Introduction to Polyoxometalate Chemistry: From Topology via Self-Assembly to Applications M.T. Pope, A. Muller. Synthetic Strategies. 1. Rational Approaches to Polyoxometalate Synthesis R.J. Errington. 2. Functionalization of Polyoxometalates: Achievements and Perspectives A. Proust, R. Villaneau. 3. From the First Sulfurated Keggin Anion to a New Class of Compounds Based on the [M2O2S2 2+ Building Block M-Mo,W E. Cadot, et al. 4. Organometallic Oxometal Clusters A. Proust, et al. Structures: Molecular and Electronic. 5. Spherical (Icosahedral) Objects in Nature and Deliberately Constructable Molecular Keplerates: Structural and Topological Aspects O. Delgado, et al. 6. Synthesis and Crystal Structure Studies of Novel Selenium- and Tellurium-Substituted Lacunary Polyoxometalates B. Krebs, et al. 7. Vibrational Spectroscopy of Heteropoly Acids H. Ratajczak, et al. 8. Bond-Stretch Isomerism in Polyoxometalates? M.-M. Rohmer, et al. 9. Quantum-Chemical Studies of Electron Transfer in Transition-Metal Substituted Polyoxometalates S.A. Borshch, H. Duclusaud. Solution Equilibria and Dynamics. 10. Aqueous Peroxoisopolyoxometalates O.W. Howarth, et al. 11. Molybdate Speciation in Systems Related to the Bleaching of Kraft Pulp F. Taube, et al. 12. NMR Studies of Various Ligands Coordinated to Paramagnetic Polyoxometalates B.A. Kim, H. So. From Discrete Clusters to Networks and Materials. 13. Molecular Aspect of EnergyTransfer from Tb3+ to Eu3+ in the Polyoxometalate Lattices: An Approach for Molecular Design of Rare-Earth Metal-Oxide Phosphors T. Yamase. 14. Conducting and Magnetic Organic / Inorganic Molecular Materials Based on Polyoxometalates L. Ouahab, et al. 15. Molecular Materials From Polyoxometalates J.J. Borras-Almenar, et al. 16. Framework Materials Composed of Transition Metal Oxide Clusters M.I. Khan. 17. Perspectives in the Solid State Coordination Chemistry of the Molybdenum Oxides P.J. Hagrman, et al. 18. Polyoxometalate Clusters in a Supramolecular Self-Organized Environment: Steps Towards Functional Nanodevices and Thin Film Applications D.G. Kurth, D. Volkmer. 19. Polyoxometalate Chemistry: A Source for Unusual Spin Topologies D. Gatteschi, et al. 20. Heteropolyanions: Molecular Building Blocks for Ultrathin Oxide Films J.D. Powell, et al. Applications: Catalysis, Biological Systems, Environmental Studies. 21. Selective Oxidation of Hydrocarbons with Hydrogen Peroxide Catalyzed by Iron-substituted Silicotungstates N. Mizuno. 22. Aerobic Oxidations Catalyzed by Polyoxometalates A.M. Khenkin, et al. 23. Polyoxoanions in Catalysis: From Record Catalytic Lifetime Nanocluster Catalysis to Record Catalytic Lifetime Catechol Dioxygenase Catalysis R.G. Finke. 24. Ribosomal Crystallography and Heteropolytungstates D. Janell, et al. 25. Photocatalytic Decontamination by Polyoxometalates A. Hiskia, et al. Index.

Polyoxometalate chemistry for nano-composite design

Contents. Self-Assembly and Nanostructures. Chemistry with Nanoparticles: Linking of Ring- and Ball-shaped Species P. Kogerler, A. Muller. Prospects for Rational Assembly of Composite Polyoxometalates N. Belai, et al. Composite Materials Derived from Oxovanadium Sulfates M.I. Khan, et al. Solid State Coordination Chemistry: Bimetallic Organophosphonate Oxide Phases of the M/Cu/O/RPO32- Family (M=V, Mo) R.C. Finn, J. Zubieta. Polyoxothiomolybdates Derived from the M02O2S2(H2O)6]2+ Building Unit F. Secheresse, et al. Lanthanide Polyoxometalates: Building Blocks for New Materials Q. Luo, et al. Organometallic Oxides and Solution Chemistry. Dynamics of Organometallic Oxides: From Synthesis and Reactivity to DFT Calculations V. Artero, et al. An Organorhodium Tungsten Oxide Cluster with a Windmill-like Skeleton: Synthesis of [(Cp*Rh)4W4O16] and Direct Observation by ESI-MS of an Unstable Intermediate [Cp*RhClWO4] K. Nishikawa, et al. Role of Alkali-metal Cation Size in Electron Transfer to Solvent-separated 1:1 [M+)(POM)] (M+=Li*, Na+, K+) Ion Pairs I.A. Weinstock, et al. New Classes of Functionalized Polyoxometalates: Organo-nitrogen Derivatives of Lindqvist Systems A.R. Moore, et al. Polyoxometalate Speciation-Ionic Medium Dependence and Complexation to Medium Ions L. Pettersson. Some Smaller Polyoxoanions. Their Synthesis and Characterization in Solution H. Nakano, et al. Magnetic, Biological, and Catalytic Interactions. Polyoxometalates: From Magnetic Models to Multifunctional Materials J.M. Clemente-Juan, et al. Magnetic Exchange Coupling and Potent AntiviralActivity of [(VO)3(SbW9O33)2]12- T. Yamase, et al. Tetravanadate, Decavanadate, Keggin and Dawson Oxotungstates Inhibit Growth of S. cerevisiae D.C. Crans, et al. Selective Oxidation of Hydrocarbons with Molecular Oxygen Catalyzed by Transition-metal-substituted Silicotungstates N. Mizuno, et al. Transition-metal-substituted Heteropoly Anions in Nonpolar Solvents Structures and Interaction with Carbon Dioxide J. Paul, et al. Polyoxometalates and Solid State Reactions at Low Heating Temperatures S. Jing, et al. Structure Determination of Polyoxotungstates Using High-energy Synchrotron Radiation T. Ozeki, et al.

Polyoxometal cations within polyoxometalate anions. Seven-coordinate uranium and zirconium heteroatom groups in [(UO2)12(μ3-O)4(μ2-H2O)12(P2W15O56)4]32− and [Zr4(μ3-O)2(μ2-OH)2(H2O)4 (P2W16O59)2]14−

Abstract Two new composite polyoxotungstate anions with unprecedented structural features, [(UO 2 ) 12 (μ 3 -O) 4 (μ 2 -H 2 O) 12 (P 2 W 15 O 56 ) 4 ] 32− ( 1 ) and [Zr 4 (μ 3 -O) 2 (μ 2 -OH) 2 (H 2 O) 4 (P 2 W 16 O 59 ) 2 ] 14− ( 2 ) contain polyoxo-uranium and -zirconium clusters as bridging units. The anions are synthesized by reaction of Na 12 [P 2 W 15 O 56 ] with solutions of UO 2 (NO 3 ) 2 and ZrCl 4 . The structure of 1 in the sodium salt contains four [P 2 W 15 O 56 ] 12− anions assembled into an overall tetrahedral cluster by means of trigonal bridging groups formed by three equatorial-edge-shared UO 7 pentagonal bipyramids. The structure of anion 2 consists of a centrosymmetric assembly of two [P 2 W 16 O 59 ] 12− anions linked by a {Zr 4 O 2 (OH) 2 (H 2 O) 4 } 10+ cluster. Both complexes in solution yield the expected two-line 31 P-NMR spectra with chemical shifts of −2.95, −13.58 and −6.45, −13.69 ppm, respectively.

Properties of an acid phosphatase from Legionella micdadei which blocks superoxide anion production by human neutrophils

The high-speed supernatant (100,000 g, 1 h) obtained after centrifuging a suspension of Legionella micdadei that had been freeze-thawed and sonicated contained (i) considerable acid phosphatase activity when assayed using 4-methylumbelliferyl phosphate (MUP) as the substrate, and a factor that blocked superoxide anion production by human neutrophils stimulated with f-Met-Leu-Phe. Chromatography of the extract on a hydroxylapatite column resolved two acids phosphatases (designated ACP1 and ACP2). Subsequent chromatography of ACP2 on a Sephadex G-150 column revealed coincident elution of phosphatase activity and neutrophil blocking activity. When heated at 45 degrees C for various periods of time, the phosphatase activity of the acid phosphatase preparation was lost at the same rate as the ability of the preparation to block superoxide anion production by neutrophils. Furthermore, preincubation of neutrophils and acid phosphatase together in the presence of a heteropolymolybdate complex that inhibits the phosphatase eliminated the effect of the L. micdadei phosphatase on neutrophil superoxide anion production. ACP2 had the following properties: pH optimum, 6.0; Km for MUP, 3.8 mM; isoelectric point, 4.5; substrate specificity, MUP greater than ADP greater than phosphoenolpyruvate greater than phosphothreonine greater than phosphoserine greater than phosphotyrosine; molecular weight (estimated by sucrose density gradient centrifugation and gel filtration chromatography), 71,000-86,000. These results indicate that a cell-associated phosphatase may play a role in the virulence of L. micdadei.

Synthesis and antitumor activity of cyclopentadienyltitanium substituted polyoxotungstate [CoW11O39(CpTi)]7− (Cp=η5-C5H5)

A novel polyoxotungstate [CoW(11)O(39)(CpTi)](7-) (Cp=eta(5)-C(5)H(5)) has been prepared. This complex exhibits the highest antitumor activity in vitro among the cyclopentadienyltitanium substituted polyoxometalates investigated and has a remarkable inhibitory action on three types of human cancer cells, SSMC-7721, HL-60 and HLC, in vivo.

Trimetallo derivatives of lacunary 9-tungstosilicate heteropolyanions. Part 1. Synthesis and charaterization

Salts of trimetallo derivatives of 9-tungstosilicate heteropolyanions have been prepared from the lacunary tungstates α- and β-[SiW9O34]10– and characterized by elemental analysis, spectroscopy and electrochemistry. Tungsten-183 NMR spectra of the (four) diamagnetic derivatives of Al and Ga consist of two lines (intensity ratio 1 : 2) as expected for the C3v structures of trisubstituted α- and β-Keggin anions. Molecular weight determinations by negative-ion fast atom bombardment mass spectrometry indicate the presence of small quantities of dimeric species (Si2W18M6) in some of the products. Electronic spectra of the derivatives of Co, Cr, Ni and Cu are consistent with octahedral co-ordination and therefore the probable attachment of a water molecule to each cation. Magnetic measurements at 5–292 K demonstrate moderate to strong antiferromagnetic interactions in the derivatives of CrIII, MnII and CuII. The complexes are stable in aqueous solution between pH ca. 5 and 10. Below pH 5 they are slowly transformed into [SiW11O39M(H2O)]n–. In addition to the expected reducibility of all of the new complexes to heteropoly blue species at negative potentials, the complexes of Fe, Cu and Mn exhibit voltammetric redox features corresponding to reduction of FeIII to FeII, CuII to Cu0, and oxidation of MnII to MnIII and MnIV.

Polyoxo Anions: Synthesis and Structure

Abstract A summary of the vast field of discrete polyoxometalate anions, which has until recently, predominantly been defined by heteropoly- and isopolymolybdates and -tungstates, and to a lesser extent, -vanadates. Unexpected developments in recent years have included the recognition of (a) a more extensive range of polyoxoniobates with an accessible alkaline solution chemistry, (b) polyoxoanions of d 8 metal centers, especially palladium(II), based on assemblies of square-planar MO 4 building units and (c) an extensive set of polyoxo(uranyl) and related actinyl clusters.

High-valent manganese in polyoxotungstates—II. Oxidation of the tetramanganese heteropolyanion [Mn4(H2O)2(PW9O34)2]10−☆

Abstract Oxidation of the heteropolyanion [Mn4II(H2O)2(PW9O34)2]10− (0) with potassium persulphate yielded mixed valence MnII,III products reproducibly isolated as the green potassium salt of [Mn4(H2O)2(PW9O34)2]9− (1) and the brown potassium-caesium salt of [Mn4(OH)2(PW9O34)2]9− (2). Coulometric and single crystal X-ray structure analysis revealed that 1 and 2 are one- and three-electron oxidized derivatives of 0 and are isostructural with 0. Slight metrical variations among 0, 1 and 2 appear in some MnO bond distances, which suggest that oxidation has occurred first at the aquated Mn(2) centres of 0. The magnetic susceptibility of 1 between 2 and 300 K shows Curie-Weiss law behaviour, θ = −27.35 K, without the maximum for χ at T ≈ 16 K previously observed for 0.

High-valent manganese in polyoxotungstates—1. Manganese(IV) keggin derivatives

Abstract Aqueous and non-aqueous soluble salts of manganese(IV)-containing Keggin polyoxotungstates [(XO 4 )W 11 Mn IV O 36 H x ] n − (X  Si, B, and Zn) have been prepared by chemical and electrolytic oxidation of corresponding manganese(II) or manganese(III) anions, and have been characterized by magnetic susceptibilities, ESR and X-ray absorption near-edge spectroscopy (XANES), in addition to conventional elemental and spectroscopic analyses. The crystal structure of dark brown K 7 [(ZnO 4 )W 11 Mn IV O 36 H] · 19H 2 O ( I ) was determined by X-ray diffraction and reveals a disordered Keggin anion. Manganese EXAFS investigation of I and the corresponding manganese(II) complex, which contains a terminal Mn II OH 2 group, strongly indicates that I contains Mn IV OH ( r Mn O ≈ 1.82 A) rather than Mn IV O.