In this review we summarise the quantum chemistry studies carried out by several groups over the last ten years on polyoxometalates, or polyoxoanions. This is an immense family of compounds made up of transition metal ions in their highest oxidation state and oxo ligands. The continuous progress of computers in general, and quantum chemistry software in particular, has enabled a number of topic...

(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...

2-Benzoylamino-N-phenyl-benzamide derivatives (5a-h) were prepared from 2-phenyl-3,1-(4H)-benzoxazin-4-one 3 and substituted anilines 4a-h in the presence of a Keggin-type heteropolyacids series (H₃PW12O40·13H₂O; H₄SiW12O40·13H₂O; H₄SiMo12O40·13H₂O; and H₃PMo12O40·13H₂O) as catalysts without solvent and under microwave irradiation. We found that the use of H₃PW12O40·13H₂O acid coupled to microw...

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...

A new monomeric diiron beta-Keggin derivative, [(CH3)2NH2]5[beta-SiFe2W10O36(OH)2(H2O)Cl].7H2O (1) with non-adjacent substituted sites has been obtained in good yield by reaction of Fe(III) cations with [gamma-SiW10O36]8- in aqueous solution. The use of hydrogen bonding counter-cations produced a disorder-free polyanion. This situation facilitates unequivocal identification of the terminal liga...

The crystal structure of the title compound, (C(6)H(12)N(5)O)(4)[W(12)(SiO(4))O(36)]·6H(2)O, consists of an α-Keggin-type [W(12)(SiO(4))O(36)](4-) polyoxidoanion, four [(2H-tetra-zol-5-yl)meth-yl]morpholinium cations and six uncoordinated water mol-ecules. In the cations, the morpholine rings display chair conformations. Extensive N-H⋯O, N-H⋯N, O-H⋯O and O-H⋯N hydrogen bonds are present in the ...

Magnetic Fe2Pt core-shell nanoparticles with 2 nm cores were synthesized with a monolayer coating of silicotungstate Keggin clusters. The core-shell composition is substantiated by structural analysis performed using high-resolution scanning transmission electron microscopy (HR-STEM) and small angle X-ray scattering (SAXS) in a liquid suspension. The molecular metal oxide cluster shell introduc...

Two hybrid assemblies (3 and 4) with two kind of nanoscaled cluster units, the spherical [Co(24)(TC4A)(6)(MO(4))(8)Cl(6)](2+) cation (1 and 2) and Keggin-type [PM(12)O(40)](3-) anion (M = Mo (1/3), W (2/4)), were solvothermally prepared and characterized, in which the spherical units are constructed by six Co(4)-p-tert-butylthiacalix[4]arene (Co(4)-TC4A) SBUs linked by eight MO(4) tetrahedrons ...

The asymmetric unit of the polyoxidometalate-based organic-inorganic hybrid title compound, (C(3)H(10)NO)(3)[PMo(12)O(40)]·3H(2)O, consists of one α-Keggin-type [PMo(12)O(40)](3-) polyoxido-anion, three independent [CH(3)-O-CH(2)-CH(2)-NH(3)](+) cations and three solvent water mol-ecules. The polyoxidoanion shows characteristic features with respect to bond lengths and angles. In the crystal st...