Synthesis and spectral properties of polynuclear titanium(4)hydroxocomplexes stabilized in solution by [PW11O39]7-heteropolyanion

An unsaturated heteropolyanion (HPA) [P11O39]7- stabilizes Ti4 hydroxo-complexes in aqueous solution (Ti:PW11 = 1:12, pH 1-3). Optical, IR, 17O and 31P NMR spectral data show that Ti4 stabilization occurs due to the interaction of Ti4 polynuclear hydroxo particles with HPA [PW11TiO40]5-. Depending on the conditions of formation of complexes, Tin-1OxHym+ hydroxo particles either attach to the oxygen atoms of HPA W-O-Ti bridges to form [PW11TiO40 · Tin-1OxHy]k-complexes ([HPA] approximately 0.01 mol x L-1), or interact with Ti4 in HPA through the terminal O atom to give [PW11O39Ti-O-Tin-1OxHe]q-complexes ([HPA] approximately 0.2 mol x L-1). Ti4 ions attach tot he peroxo groups on treatment of the complexes of the first type with H2O2. 24 refs.; 4 figs.; 4 tabs