Topic
Polyoxometalate
About: Polyoxometalate is a research topic. Over the lifetime, 3493 publications have been published within this topic receiving 94123 citations. The topic is also known as: POM.
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TL;DR: The use of two organosilanes as reagents enabled the preparation of the functionalized polyoxometalate [alpha2-P2W17O61(RSi)2O]6- in good yield and ESI-MS analyses generated reduction processes which were compared to those related to [PMo11VO40]4-, the highly reducible Keggin polyoxometricalate.
Abstract: In the field of functionalized polyoxometalates, organosilyl derivatives of polyoxotungstate constitute a special class of hybrid organic-inorganic system. The first organosilyl derivative of the monovacant Dawson heteropolyoxotungstate [alpha2-P2W17O61]10- was obtained by three different methods. The use of two organosilanes as reagents enabled the preparation of the functionalized polyoxometalate [alpha2-P2W17O61(RSi)2O]6- in good yield. Electrospray (ESI-MS) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, and 183W, 31P, and 29Si NMR spectroscopy were used to characterize the composite systems. In several cases, ESI-MS analyses generated reduction processes which were compared to those related to [PMo11VO40]4-, the highly reducible Keggin polyoxometalate.
53 citations
TL;DR: In this article, the synthesis of highly ordered mesoporous frameworks consisting of nanocrystalline Co3O4 and Keggin-type tungstophosphoric acid (HPW12O40, HPW) compounds using the hard-templating method was reported.
Abstract: We report the synthesis of highly ordered mesoporous frameworks consisting of nanocrystalline Co3O4 and Keggin-type tungstophosphoric acid (HPW12O40, HPW) compounds using the hard-templating method. The resulting materials feature a Co3O4/HPW solid solution structure with different HPW loadings, i.e., 6, 11, 15, and 36 wt %. Characterization by small-angle X-ray scattering (SAXS), high-resolution transmission electron microscopy (TEM), and N2 physisorption measurements reveal that all mesoporous frameworks possess a three-dimensional cubic symmetry with large internal Brumauer−Emmett−Teller (BET) surface area (87−141 m2g−1) and narrow sized pores (ca. 4 nm). The Keggin structure of the incorporated PW12O403− clusters within the composite frameworks was confirmed with X-ray diffused scattering and atomic pair distribution function (PDF) analysis, X-ray photoelectron spectroscopy (XPS), infrared (IR), and diffuse-reflectance UV/vis spectroscopy. Catalytic studies have indicated that these Co3O4/HPW composit...
53 citations
TL;DR: The reaction between PW9O349- and NpO2+ has yielded the first structurally characterized neptunyl(V) polyoxometalate complex, which is isostructural with the uranyl(VI) analogue, and there is also spectroscopic evidence for its existence in solution.
Abstract: The reaction between PW9O349- and NpO2+ has yielded the first structurally characterized neptunyl(V) polyoxometalate complex, [Na2(NpO2)2(A-PW9O34)2]14-. This complex is isostructural with the uranyl(VI) analogue, and there is also spectroscopic evidence for its existence in solution. The complex is readily extracted into toluene, and this may have significance in the sequestering and/or separation of the neptunyl ion in terms of nuclear waste management.
53 citations
TL;DR: In this article , a polyoxometalate (POM)-incorporated ZnIn2S4 dual-functional photocatalytic system was used for anaerobic oxidation of benzyl alcohol with concomitant H2 production.
Abstract: Efficient aromatic alcohol oxidation with simultaneous H2 evolution under aqueous conditions is achieved in a polyoxometalate (POM)-incorporated ZnIn2S4 dual-functional photocatalytic system. The synergy between HPM and ZIS contributes to the formation of a Z-type heterojunction structure and thus enhances redox capacity. Moreover, the sub-nanometer size of POM clusters endows molecular-level interfacial contact, which acts as an "electron bridge" ensuring faster interfacial charge transfer kinetics. Therefore, an impressive nearly 100% yield of benzaldehyde and 10.6 mmol·g−1·h−1 H2-evolution rate are observed for POM/ZIS nanocomposites even under an anaerobic atmosphere with water as the solvent. This is the first application of POM-based materials in the anaerobic oxidation of benzyl alcohol with concomitant H2 production. This study expands the possibilities for designing multifunctional POM-based photocatalysts for economic and ecological photoredox applications.
53 citations
TL;DR: The first example of oxygen-atom vacancy formation at the surface of a polyoxometalate is reported, highlighting the ability of apolyoxovanadate-alkoxide cluster, [V6O7(OCH3)12]1-, to function as a homogeneous model for reducible metal oxides.
Abstract: We report the first example of oxygen-atom vacancy formation at the surface of a polyoxometalate, highlighting the ability of a polyoxovanadate-alkoxide cluster, [V6O7(OCH3)12]1–, to function as a homogeneous model for reducible metal oxides. The removal of an oxide ion from [V6O7(OCH3)12]1– results in the formation of a reactive vanadium(III) cation within the multimetallic framework. Generation of [V6O6(OCH3)12]1– is confirmed by 1H NMR, infrared and electronic absorption spectroscopies, as well as electrospray ionization mass spectrometry. The consequences of oxygen atom removal on the electrochemical profile of the assembly are assessed, revealing that stabilization of the reduced cluster is achieved through delocalized electron density. The oxygen-atom vacancy permits activation of O2, demonstrating the ability of polyoxovanadate-alkoxide clusters to serve as both structural and functional models of reducible metal oxides.
53 citations