Titanium(IV) polynuclear hydroxo complexes stabilized in solution by [PW11O39](7-) heteropolyanion

[PW11O39](7-) heteropolyanion (HPA) stabilizes Ti(IV) in aqueous solution at Ti:PW11 ratios from 1 to similar to 12 and pH 1-3. Ti(IV) is completely precipitated under these conditions in the absence of HPA. Differential dissolution phase analysis, optical IR, P-31 and O-17 NMR spectra show that one Ti((IV)) ion is incorporated into the Keggin lattice. The other ions, most probably, are located on the HPA surface in the form of oligomeric hydroxo fragments: [(PW11TiO40)-O-IV. Tin-1 (OxHy)-O-IV](k-). Both types of Ti(IV) ions bind peroxo groups on interaction of the complex with H2O2.