Transformations of dimeric and tetrameric glycolato peroxotitanates and their thermal decompositions for the preparations of anatase and rutile oxides

Glycolato peroxotitanates [Ti-2(O-2)(2)(glyc)(2)(H2O)(4)]center dot 2H(2)O (1) and (NH4)(6)LTi4(O-2)(4)O-2(glyc)(4)(Hglyc)(2)]center dot 7H(2)O (2) (H(2)glyc = glycolic acid) have been isolated from the reactions of titanium tetra-n-butyl oxide with glycolic acid and hydrogen peroxide. Transformations of glycolato peroxotitanates depend on pH values of the solutions, that is pH = 1.0 for 1 and pH = 5.0 for 2 respectively. Decomposition of 1 results in the formation of the pure anatasetype TiO2 at 500 degrees C, while 2 results in the formation of the pure rutile-type TiO2 at 700 degrees C. The titanium atoms in 1 and 2 exist in pentagonal bipyramidal coordination environment. 1 is a dinuclear neutral complex containing two Ti(O-2) (H2O)(2) cores, which are linked by two deprotonated glycolate ligands. 2 comprises a tetranuclear titanium anion structure, which consists of two Ti-2(O-2)(2) cores inter-linked through two bridged oxygen atoms. The XRD patterns and Raman spectra of TiO2 annealed from 1 and 2 at different temperature were explored.