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.

Structural and catalytic performance of a polyoxometalate-based metal-organic framework having a lanthanide nanocage as a secondary building block.

Abstract: A polyoxometalate-based lanthanide−organic framework was achieved using the {[Ho4(dpdo)8(H2O)16BW12O40] (H2O)2}7+ nanocage as a secondary building block for the heterogeneous catalysis of phosphodiester cleavage in an aqueous solution.

Reversible electron-transfer reactions within a nanoscale metal oxide cage mediated by metallic substrates.

Abstract: Transition metal oxides exhibit a rich collection of electronic properties and have many practical applications in areas such as catalysis and ultra-high-density magnetic data storage. Therefore the development of switchable molecular transition metal oxides has potential for the engineering of single-molecule devices and nanoscale electronics. At present, the electronic properties of transition metal oxides can only be tailored through the irreversible introduction of dopant ions, modifying the electronic structure by either injecting electrons or core holes. Here we show that a molybdenum(VI) oxide 'polyoxometalate' molecular nanocluster containing two embedded redox agents is activated by a metallic surface and can reversibly interconvert between two electronic states. Upon thermal activation two electrons are ejected from the active sulphite anions and delocalized over the metal oxide cluster cage, switching it from a fully oxidized state to a two-electron reduced state along with the concomitant formation of an S-S bonding interaction between the two sulphur centres inside the cluster shell.

Surface Functionalization of Semiconductor and Oxide Nanocrystals with Small Inorganic Oxoanions (PO43–, MoO42–) and Polyoxometalate Ligands

Abstract: In this work, we study the functionalization of the nanocrystal (NC) surface with inorganic oxo ligands, which bring a new set of functionalities to all-inorganic colloidal nanomaterials. We show that simple inorganic oxoanions, such as PO43– and MoO42–, exhibit strong binding affinity to the surface of various II–VI and III–V semiconductor and metal oxide NCs. ζ-Potential titration offered a useful tool to differentiate the binding affinities of inorganic ligands toward different NCs. Direct comparison of the binding affinity of oxo and chalcogenidometallate ligands revealed that the former ligands form a stronger bond with oxide NCs (e.g., Fe2O3, ZnO, and TiO2), while the latter prefer binding to metal chalcogenide NCs (e.g., CdSe). The binding between NCs and oxo ligands strengthens when moving from small oxoanions to polyoxometallates (POMs). We also show that small oxo ligands and POMs make it possible to tailor NC properties. For example, we observed improved stability upon Li+-ion intercalation int...

Green Oxidation Reactions by Polyoxometalate-Based Catalysts: From Molecular to Solid Catalysts

Abstract: This article summarizes our recent developments for H2O2- and O2-based green oxidation reactions by polyoxometalates (POMs) and related compounds. POM-based structurally controlled molecular catalysts exhibit high catalytic performance for epoxidation and sulfoxidation with H2O2. These molecular catalysts can be immobilized on the organic–inorganic hybrid support with covalently anchoring N-octyldihydroimidazolium cation fragments via the anion exchange. In addition, we have developed supported metal hydroxide catalysts such as Ru(OH)x/Al2O3 and Cu(OH)x/TiO2 on the basis of the information of the catalytically active sites with POMs. By using these supported metal hydroxide catalysts, novel aerobic oxidative synthesis of nitriles and amides, and efficient aerobic oxidative homocoupling of alkynes can be realized.