Hydrothermal Synthesis and Structural Characterization of Two New Three-Dimensional Oxyfluorinated Titanium PhosphatesTi4(HPO4)2(PO4)4F2·C4N2H12·H2O and Ti4(HPO4)2(PO4)4F2·C2N2H10·H2O

Abstract

Two new organo-templated three-dimensional fluorinated titanium phosphates Ti4(HPO4)2(PO4)4F2·C4N2H12·H2O 1 and Ti4(HPO4)2(PO4)4F2·C2N2H10·H2O 2 have been prepared hydrothermally in the presence of piperazine (C4N2H10) and ethylenediamine (C2N2H8) as templates, respectively. The as-synthesized products are characterized by powder X-ray diffraction, IR spectroscopy, and thermogravimetric and differential thermal analyses (TG-DTA). The structures have been solved by single-crystal X-ray diffraction analysis. The compound 1 crystallized in the monoclinic space group C2/c (no. 15), with M=907.61 g/mol, a=16.6549(17) Å, b=6.3378(6) Å, c=22.208(2) Å, β=94.862(4)°, V=2335.7(4) Å3, Z=4, R1[I>2σ(I)]=0.0393, wR2[I>2σ(I)]=0.107 and the compound 2 in the monoclinic space group C2/m (no. 12), with M=880.56 g/mol, a=16.6324(14) Å, b=6.3219(6) Å, c=11.0725(10) Å, β=94.362(2)°, V=1160.88(18) Å3, Z=2, R1[I>2σ(I)]=0.0461, wR2[I>2σ(I)]=0.1403. They have similar three-dimensional frameworks built up from TiO6, TiO5F octahedral, PO4, and PO3(OH) tetrahedral units. There exist two types of 8-membered ring channels along the b axis in which the diprontonated piperazine or ethylenediamine molecules are entrapped and along the c axis in which water molecules are entrapped.