Pure ti-based mixed oxides prepared from the thermal decompositions of molecular precursors of peroxo complexes coordinated with tris(hydroxycarbonylmethyl)amine trivalent anion titanate(IV)

Abstract

Different peroxo titanate (IV) complexes coordinated with tris(hydroxycarbonylmethyl) amine trivalent anion including ammonium, potassium, strontium and barium salts (NH4)(4)[Ti2O(O-2)(2)(ta)(2)]-4H(2)0 (1), K-4[Ti2O(O-2)(2)(ta)(2)]-6H(2)O (2), Sr-2[Ti2O(O-2)(2)(ta)(2)]-10H(2)O (3) and Ba-2[Ti2O(O-2)(2)(ta)(2)]-10H(2)O(4) were obtained directly from the triad system of TiCl4-H2O2-H(3)ta [H(3)ta = tris(hydroxycarbonylmethyl) amine] in pH 2.5 similar to 4.0. These complexes were characterized with elemental analysis, UV-vis and IR spectra. X-ray structural analysis shows that all complexes contain a similar dimeric anion structure, in which titanium atom is coordinated heptagonally by a peroxo group, a tetradenatate tris(hydroxycarbonylmethyl)amine trivalent anion ligand and a bridging oxygen atom. The cation Sr2+ and Ba2+ are coordinated enneahedrally and decagonally by water molecules and carboxyl groups of tris-(hydroxycarbonylmethyl)amine trivalent anion ligand respectively. The ammonium, strontium and barium salts can be decomposed stoichiometrically into the expected low-temperature phases of rutile TiO2, SrTiO3 and tetragonal BaTiO3 at the temperature of 600 degreesC respectively, which has been confirmed by XRD characterization.