core-shell 12-tungstophosphoric acid/tio2 (hpw/tio2) nanoparticles at 10 and 20% of hpw have been synthesized by simple in-situ sol- gel method. characterization of the samples was carried out by x-ray diffraction (xrd), scanning electron microscopy (sem), fourier transform infrared (ftir). the x-ray diffraction patterns of as prepared solid samples, indicated characteristic peaks of titania wi...

We report examples of crystal surface modification of polyoxometalate open frameworks whereby the use of pyrrole or aniline as monomers leads to the formation of the corresponding polymers via an oxidative polymerization process initiated by the redox active POM scaffolds. Guest-exchange experiments demonstrate that the polymers can finely tune the guest exchange rate and their structural integ...

A study of the effects of the interactions with amino acids on the vibrational spectra of Keggin heteropolyanions (Na(n)H(3-)n[XM(12)O(40)](n-); n = 0,1,2,3; X = P(V), Si(IV), M = W(VI), Mo(VI)) has been performed. Interactions occurred for all of the studied compounds leading to changes and splits in the stretching frequencies. Depending on the amino acid type, the IR bands for interbridge str...

The tungsten-182 Mössbauer spectra of a series of Keggin structure heteropolytungstates, [EW12O40]n- are reported. There is a very considerable variation in quadrupole coupling at the tungsten nucleus indicating considerable asymmetry in the electron distribution for the more electronegative elements E. The quadrupole coupling correlates well with the structural data, in particular with the dis...

A comparative study investigating the effects of metal substitution on the photocatalytic activity of metal oxide cluster anions is presented. The study shows that metal functionalization can be used to alter the photochemical properties of monolacunary tungstate - based Keggin clusters (α-[TM(H2O)SiW11O39](n-) (M = Co(2+), Cu(2+), Ni(2+), Mn(2+))). It is demonstrated that the photoactivity for...

Mixed-addenda vanadium substituted polyoxometalate supported on anatase TiO2 crushed nano leaf was synthesized by an unusual reaction with titanium tetraisopropoxide at 100 ºC via sol–gel method under oil-bath condition. The materials characterized by XRD, TEM,  IR and UV–vis  techniques.  In  the  present  work,  efficient  oxidative  of  thiols  with  polyoxometalate-TiO2/hydrogen  peroxide  ...