3D-architecture via self-assembly of Krebs-type polyoxometalate {[Na10(H2O)26][Sb2W20Zn2O70(H2O)6]}

A tetrahedron-shaped polyoxoantimotungstate encapsulating a hexanuclear octahedral lanthanide-oxo cluster for an amperometric bromate sensor

An inorganic hexalanthanide-oxo-cluster-encapsulated antimotungstate, K2Na3H43[Nd6(OH)6(H2O)6(B-α-SbW9O33)4]2·67H2O (1), has been successfully synthesized by a facile one-step hydrothermal reaction method. The tetrahedron-shaped two-shell {Nd6(OH)6(H2O)6(B-α-SbW9O33)4}(1a) polyanion is composed of a novel pure lanthanide-oxo {Nd6(μ3-OH)6(H2O)6} octahedron and {(B-α-SbW9O33)4} tetrahedron. After being effectively loaded onto a glassy carbon electrode (GCE) by electrostatic adsorption using polydiallyldimethyl ammonium chloride (PDDA)-functionalized multi-walled carbon nanotubes (MWCNTs), compound 1 exhibits electrochemical activity for the reduction of bromate ions with good selectivity, a high sensitivity of 186 μA mM-1 and a detection limit that has reached 1.9 μM. To the best of our knowledge, this is the first example of an amperometric bromate sensor based on Ln-containing antimotungstates, which will provide new materials for electrochemical sensors.

Inorganic–organic hybrid supramolecular architectures based on Keggin polyoxometalates and crown ether: synthesis, crystal structure and electrochemical properties

Novel supramolecular assemblies built from Keggin-type polyoxometalate and [18]-crown-6 ether building blocks exhibit unique propeller-like supramolecular host–guest structures.

New Robust Luminescent Supramolecular Assemblies Based on [Ln(Mo8O26)2]5- (Ln = Eu, Sm) Polyoxometalates

This work highlights for the first time the photoluminescence (PL) properties of two new [Ln(Mo₈O₂₆)₂]^5- (Ln = Eu, Sm) lanthanide-containing polyoxometalates. Stable crystals of their tetrabutylammonium salts were synthesized, and their structures were confirmed by single-crystal X-ray diffraction. The robustness of the [Ln(Mo₈O₂₆)₂]^5- complexes in an acetonitrile solution has been evidenced by Fourier transform Raman and PL spectroscopies. The tetraphenylphosphonium derivatives were obtained by a salt metathesis reaction. The two series exhibit high thermal stability in air and are efficient phosphors at room temperature.

Carboxyethyltin and transition metal co-functionalized tungstoantimonates composited with polypyrrole for enhanced electrocatalytic methanol oxidation

Carboxyethyltin and first-row transition metals (TMs) were firstly introduced into trivacant Keggin-type tungstoantimonate in an aqueous solution, leading to the formation of four crystalline organic-inorganic hybrid sandwich-type polyoxometalates (POMs), formulated as Na10-x-yKyHx[((TM)(H2O)3)2(Sn(CH2)2COO)2(SbW9O33)2]·nH2O (SbW9-TM-SnR, TM = Mn, Co, Ni, Zn; x = 1, 1, 0, 0; y = 0, 5, 5, 2; n = 18, 24, 24, 22, respectively). SbW9-TM-SnR exhibit high catalytic ability for the oxidation of cyclohexanol. Meanwhile, SbW9-TM-SnR were composited with polypyrrole (PPy) through an electropolymerization process, forming PPy-SbW9-TM-SnR, on which platinum (Pt) was further electro-deposited to prepare PPy-SbW9-TM-SnR/Pt for electrocatalytic methanol (CH3OH) oxidation in acid solution. The composition and morphology of PPy-SbW9-TM-SnR/Pt were determined by IR, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The electrochemical experimental results show that SbW9-TM-SnR and PPy obviously enhance the electrocatalytic and anti-intoxication abilities of Pt, and the highest peak current density of 0.87 mA cm-2, corresponding to 1.85 and 1.43 times higher than those of pure Pt and PPy/Pt electrodes respectively, is acquired for the PPy-SbW9-Ni-SnR/Pt composite electrode. These findings may enlarge the application of PPy and POMs in the electrocatalytic field.

Synthesis, characterization, and photoluminescence properties of three two-dimensional lanthanide-containing Dawson-type polyoxometalates

Three isostructural lanthanide-containing polyoxometalates with 2D network architectures were successfully obtained under hydrothermal conditions.