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.

Modular Inorganic Polyoxometalate Frameworks Showing Emergent Properties: Redox Alloys

Abstract: Alloy, alloy: A pure cobalt-based Keggin network linked by W-O-Co interactions is “alloyed” with a pure manganese-based Keggin network, linked by W-O-Mn interactions. These isostructural alloys are solid solutions of the Co and Mn nets. The alloys are prepared by the stoichiometric mixing of the components of each discrete network, leading to a series of single-crystalline mixed transition-metal frameworks with novel redox properties.

Fabrication of an inorganic–organic hybrid based on an iron-substituted polyoxotungstate as a peroxidase for colorimetric immunoassays of H2O2 and cancer cells

Abstract: Fabrication of a folate and iron-substituted polyoxometalate [(FeOH2)2SiW10O36] has been achieved through self-assembly of folate and polyoxometalate molecules, which was characterized by IR spectroscopy, and transmission electron microscopy (TEM). This inorganic–organic hybrid has been proven to possess intrinsic peroxidase-like activity in the oxidation of dyes, which can catalyze oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 to form a blue color in aqueous solution. The TMB/POM/H2O2 system provides a new approach to detect H2O2 with good sensitivity, wide linear range (from 1.34 × 10−7 to 6.7 × 10−5 mol L−1), low detection limit (1 × 10−7 mol L−1) and fast response towards H2O2 instead of an enzyme biosensor. In addition, this unique hybrid FA–Fe2SiW10 is inexpensive, easily prepared, and very efficient in the colorimetric multiplexed immunoassay of cancer cells.

χ‐Octamolybdate [MoV4MoVI4O24]4−: An Unusual Small Polyoxometalate in Partially Reduced Form from Nonaqueous Solvent Reduction

Abstract: The first mixed-valent octamolybdate anion [Mo(V)(4)Mo(VI)(4)O(24)](4-), termed χ-octamolybdate due to its shape, was obtained by partial reduction of α-(Bu(4)N)(4)-[Mo(8)O(26)] in dry acetonitrile. Single-crystal X-ray structure analysis revealed that the anion includes an unusual Mo(V)(4)O(8) cubane-like cluster core, whose four side faces are capped by four MoO(4) units to form a crosslike cluster. X-ray photoelectron spectroscopy (XPS) and bond valence sum (BVS) calculations were carried out to validate the presence of mixed-valent Mo centers.

Direct imaging of the structure, relaxation, and sterically constrained motion of encapsulated tungsten polyoxometalate lindqvist ions within carbon nanotubes.

Abstract: The imaging properties and observation of the sterically regulated translational motion of discrete tungsten polyoxometalate Linqvist ions (i.e., [W(6)O(19)](2-)) within carbon nanotubes of specific internal diameter are reported. The translational motion of the nonspheroidal anion within the nanotube capillary is found to be impeded by its near-perfect accommodation to the internal van der Waals surface of the nanotube wall. Rotational motion of the anion about one remaining degree of freedom permits translational motion of the anion along the nanotube followed by locking in at sterically favorable positions in a mechanism similar to a molecular ratchet. This steric locking permits the successful direct imaging of the constituent octahedral cation template of individual [W(6)O(19)](2-) anions by high resolution transmission electron microscopy thereby permitting meterological measurements to be performed directly on the anion. Direct imaging of pairs of equatorial W(2) atoms within the anion reveal steric relaxation of the anion contained within the nanotube capillary relative to the bulk anion structure.