Hydrothermal Synthesis, Crystal Structure and Characterizations of Four New Metal Phosphonates with Layered Structure

Abstract

AbstractBy using piperazine as a structure‐directing agent, four new metal phosphonates with layered structure, [pzH2]0.5[ML(H2O)]·1.5H2O [M = Co (1), Ni (2), Zn (3)] and [pz]0.5[Sb2L2]·H2O (4) (H3L = 2‐hydroxyphosphonoacetic acid; pz = piperazine), have been hydrothermally synthesized and structurally characterized by single‐crystal and powder X‐ray diffraction, infrared spectroscopy, elemental analysis and thermogravimetric analysis. Compounds 1–3 are isostructural and comprise MO6 octahedra and CPO3 tetrahedra connected by [O3PCH(OH)CO2]3– to form a 2D layered structure with a one‐dimensional channel system along the a axis direction. In compound 4, two SbO4E trigonal bipyramids (E is a lone pair of electrons, which occupy an axial position) are interconnected into a dimer by corner‐sharing. The so‐built dimers are bridged by the CPO3 tetrahedra into a 2D layered structure with a one‐dimensional channel system in the c axis direction. The protonated piperazine cations for compounds 1–3 and the piperazine molecules for compound 4 are located between two adjacent layers.