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: In this article, a charge transfer (CT) salt was prepared from planar arene donors and planar polyoxometalates by attaching a cationic anchor onto the arene which then clings to the POM anion by Coulombic forces.
Abstract: Spherical polyoxometalates (POMs) such as M6O192- and SiM12O404- (with M = Mo or W) and planar arene donors (anthracenes and pyrenes) can be cocrystallized (despite their structural incompatibility) by attaching a cationic “anchor” onto the arene which then clings to the POM anion by Coulombic forces. As a result, novel charge-transfer (CT) salts are prepared from arene donors and Lindqvist-type [M6O19]2- and Keggin-type [SiM12O40]4- acceptors with overall 2:1 and 4:1 stoichiometry, respectively. The CT character of the dark-colored (yellow to red) crystalline materials is confirmed by the linear Mulliken correlation between the CT transition energies and the reduction potentials of the POM acceptors, as well as by the transient (diffuse reflectance) absorption spectra (upon picosecond laser excitation) of anthracene or pyrene cation radicals (in monomeric and π-dimeric forms). X-ray crystallographic studies reveal a unique “dimeric” arrangement of the cofacially oriented arene couples which show contact ...
116 citations
TL;DR: The Brønsted acid sites generated in situ from H(2) have been demonstrated to play a key role in the formation of sorbitol.
116 citations
TL;DR: The functionalization of a pre-formed, high oxidation state {CeIV MnIV 6} cluster with a lacunary phosphotungstate, [alpha-P2 W15 O 56]12-, exemplifies a straightforward route for grafting redox-active building blocks to existing Mn-carboxylate clusters and modeling their deposition onto metal oxide surfaces.
116 citations
TL;DR: Two new Cu(II) azido polyoxometalates compounds have been synthesized, and their structures were determined by X-ray crystallography, which revealed an overall antiferromagnetic behavior for both compounds.
Abstract: Two new Cu(II) azido polyoxometalates compounds have been synthesized, and their structures were determined by X-ray crystallography. The compound Na14[SiW9O34Cu3(N3)2(OH)(H2O)]2·24H2O (1) is built from two [SiW9O34Cu3(μ1,1,3-N3)2(μ-OH)(H2O)]7- subunits where the copper centers, connected by two azido ligands and one hydroxo group, form a nearly equilateral triangle. The two subunits are related by an inversion center and connected via the two μ1,1,3-N3 ligands in an end-to-end fashion, affording a hexanuclear Cu(II) cluster. Linkage of these fragments via CuOW bonds leads to a bidimensional arrangement of the polyoxometalate units. The complex LiK14Na9[P8W48O184Cu20(N3)6(OH)18]·60H2O (2) consists of two {Cu5(OH)4}6+ and two {Cu5(OH)2(μ1,1,3,3-N3)}7+ subunits connected via four μ-OH and four μ1,1-N3 additional ligands, the 20 copper centers being encapsulated in the [P8W48O184]40- crown polyoxotungstate ligand. 1 represents the first multidimensional compound based on azido polyoxometalate (POM) units, an...
115 citations
TL;DR: In this article, the performance of the Ru-containing polyoxometalate (POM) water oxidation molecular catalyst, Rb8K2[{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]10− (Rb8k2-1), has been studied by cyclic and rotating disk electrode voltammetric methods in aqueous media under acidic and neutral pH conditions using bare glassy carbon (GC) and graphene modified GC electrodes.
Abstract: The electrochemistry of the Ru-containing polyoxometalate (POM) water oxidation molecular catalyst, Rb8K2[{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2]10− (Rb8K2-1), has been studied by cyclic and rotating disk electrode voltammetric methods in aqueous media under acidic and neutral pH conditions using bare glassy carbon (GC) and graphene modified GC electrodes. High concentrations of supporting electrolyte are needed in neutral pH conditions to overcome the electrical double layer effect associated with the highly negatively charged 1. Complex 1 can be confined within the highly porous wet graphene film to form a stable modified electrode, which shows excellent catalytic activity and high stability toward the water oxidation reaction under neutral pH conditions, particularly in the presence of 1.0 M Ca(NO3)2. The catalytic activity of the graphene supported 1electrode is nearly two orders of magnitude higher than that reported with a polymer coated multiwalled carbon nanotube supported 1electrode when both are employed at a moderate overpotential of 0.35 V.
114 citations