Hydrothermal Synthesis and Characterization of Two New Three-Dimensional Titanium Phosphates

Abstract

Two new three-dimensional titanium phosphates with the formulas Ti2(HPO4)3(PO4)·0.5C4N2H12 (1) and Ti7(HPO4)6(PO4)6·C6N2H14 (2) have been prepared hydrothermally from titanium powder, phosphoric acid, and structure-directing organic amines. The as-synthesized products were characterized by powder X-ray diffraction, IR spectroscopy, thermogravimetric, and differential thermal analyses (TG-DTA). The structures were solved by single-crystal X-ray diffraction analysis. Crystal data are as follows: Ti2(HPO4)3(PO4)·0.5C4N2H12 (1), monoclinic, space group P21/n (no. 14), a = 10.7455(11) A, b = 6.3469(6) A, c = 20.4800(19) A, β = 104.286(3)°, V = 1353.6(2) A3, Z = 4; Ti7(HPO4)6(PO4)6·C6N2H14 (2), trigonal, space group R-3 (no. 148), a = 16.8640(14) A, b = 16.8640(14) A, c = 12.334(2) A, V = 3037.7(6) A3, Z = 3. Both structures are of the open-framework type, and the frameworks are built from TiO6 octahedra and PO4, PO3(OH), and/or PO2(O)(OH) tetrahedral units. There exist eight-membered ring channels, in which t...