Polyoxometalates (POMs) have been a popular motif in crystal engineering. In this work, seven ionic crystals based on Keggin- or Dawson-type POMs and mononuclear Bi(III) complexes were synthesized. The center exhibited triangular dodecahedron, square antiprism, pseudo-cubic eight-coordination geometries, with DMSO DMF as ligands. showed polymorphic transformations, high proton conductivities de...

Keggin heteropolyacids (HPAs) are metal–oxygen clusters with strong Bronsted acidity. The conversion of HPAs to metal salts can result in Lewis acidity, improving their performance oxidation reactions. In this review, the main routes for synthesis Keggin-type salts, as well use catalysts processes a plethora substrates, such monoterpenes, olefins, aldehydes, terpene alcohols, and aromatics, des...

Nine new Sb-bicapped α-Keggin-type heteropolyoxoniobates (HPNb) were synthesized under hydrothermal conditions. Among them, the As-centered HPNb was never reported before, and the two dimer compounds are the biggest isolated HPNbs at present.

A zirconium modified MCM-48 mesoporous material was synthesized by surfactant-templated method. Surface grafting Zr-MCM-48 with tungstophosphoric acid led to a great enhancement of both the number of the Brønsted acid sites and acidity strength in comparison with the bare support. At 100 ̊C, the 30 wt% H3PW12O40/Zr-MCM-48 contained 174 mol/g Brønsted acid sites which were 21.7 times greater tha...

In the presence of Keggin-type phosphovanadomolybdic acids, e.g., H6PV3Mo9O40, oxidative dimerization of various kinds of primary thioamides including aromatic, heterocyclic, and aliphatic ones efficiently proceeded to give the corresponding 3,5-disubstituted 1,2,4-thiadiazoles in excellent yields.

Threading molecular square "beads" on a twofold interpenetrated diamondoid skeleton gives a new type of 3D metal-organic polyrotaxane framework with large channels, in which nanosized Keggin anions as guests are encapsulated for the first time.

(C5H7N2)3(AsMo12O40)·2C5H6N2·1.5H2O was hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Crystal data: monoclinic, P21/n, a = 13.310(3), b = 22.399(5), c = 19.820(4) Å, β = 99.99(3) ◦, V = 5819(2) Å3, Z = 1, wR(F2) = 0.1345. The structure consists of Keggin-type [AsMo12O40]3− polyoxoanions. The title compound has a high catalytic activity for the ox...

When using heteropolycompounds in the selective oxidation of isobutane to methacrolein and methacrylic acid, both the keeping of the primary structure (Keggin units) and the presence of acidic sites are necessary to obtain the desired products. The structural evolution of supported (NH4)3HPMo11VO40 (APMV) catalysts under preliminary thermal oxidizing and reducing treatments was investigated. Va...

Two polyoxometalate Keggin-type anions, alpha-PM12O40(3-) (M = Mo, W), were transferred to the gas phase by electrospray; their electronic structure and stability were probed by photoelectron spectroscopy. These triply charged anions were found to be highly stable in the gas phase with large adiabatic electron detachment energies of 1.7 and 2.1 eV for M = Mo and W, respectively. The magnitude o...