The interaction between the plenary Keggin H3PW12O40, lacunary Keggin K7PW11O39 and the Eu(III)-substituted Keggin K4EuPW11O39 (Eu-Keggin) type polyoxometalates (POMs), and the proteins human and bovine serum albumin (HSA and BSA) was studied using steady state and time-resolved Eu(III) luminescence and tryptophan (Trp) fluorescence spectroscopy. The excitation spectrum of the Eu-Keggin POM is ...

The molecular structures and surface chemistry of mixed metal oxide heteropolyoxo vanadium tungstate (H(3+x)PW(12-x)V(x)O(40) with x = 0, 1, 2, and 3) Keggin nanoparticles (NPs), where vanadium is incorporated into the primary Keggin structure, and supported VO(x) on tungstophosphoric acid (TPA, H(3)PW(12)O(40)), where vanadium is present on the surface of the Keggin unit, were investigated wit...

The structural evolution of Keggin-type heteropolyoxomolybdates (HPOM) during thermal treatment in propene and in propene and oxygen in the temperature range from 300 to 773 K was investigated by in situ X-ray diffraction (XRD) and in situ X-ray absorption spectroscopy (XAS) combined with mass spectrometry. During treatment in propene or hydrogen and at reaction temperatures above 673 K, the in...

Titania supported vanadomolybdophosphoric acid (VMPA) catalysts with vanadium in different positions, incorporated into the molybdophosphoric acid structure by substituting for molybdenum and cation exchanged on the molybdophosphoric acid surface, were synthesized. The catalysts were characterized by XRD, FT-IR, Raman spectroscopy, TPR, XPS, and ESR techniques. The FT-IR and Raman spectral anal...

Reaction products of titanium(IV) sulfate in HCl-acidic aqueous solution with the dimeric species linked through three intermolecular Ti-O-Ti bonds of the two trititanium(IV)-substituted α-Keggin polyoxometalate (POM) subunits are described. Two novel titanium(IV)-containing α-Keggin POMs were obtained under different conditions. One product was a dimeric species through two intermolecular Ti-O...

Molybdenum-based Keggin polyoxometalates (POMs) containing vanadium, with the formula H3+xPMo12 xVxO40 (MPAV) and x varying from0 to 3, exhibit unique catalytic properties because of their bifunctional nature and have been investigated as catalysts both for acidic and for oxidative reactions. 3 The addition of vanadium centers are beneficial for redox catalysis, shifting the molybdophosphoric a...

In the work reported in this paper, we demonstrate that Ag–Keggin ion colloidal particles are excellent templates for the synthesis of organized assemblies of silver nanoparticles, wherein the Keggin ion host plays the role of a UV-switchable reducing agent. More specifically, we investigate the formation of aqueous colloidal particles of Ag ions complexed with phosphotungstate (PW12O40) 32 Keg...

Partial hydrolysis of AlCl3 with Ca(OH)2 and the amino acid glycine enables the selective transformation of the Al13 Keggin structures, outlining the ε → δ → γ isomerization process. Through this, a new γ-Al13 Keggin structure was able to be isolated and characterized through (27)Al NMR and single-crystal XRD.

Six new compounds [(CpTi)X, Cp=upsilon(nabla)-c(nabla)H(nabla), X=Ge, Ga, B) have been prepared and their Keggin structures determined by elementary analysis, IR, UV, (infinity)H NMR and (infinity for all)WNMR spectrometry. The results show that the complexes retain Keggin structure. The complexes exhibit antitumoral activity in vitro as shown by MTT experiment.

HeteroPolyAcids (HPA's) are a class of solid acids that have broad applications in many fields of science and technology, including catalysis and chemical engineering. The proton locations within the thermally stable and commonly known Keggin unit, which is the primary structure building unit/block, has remained undetermined in anhydrous HPAs, despite numerous theoretical and experimental effor...