Hydrothermal Synthesis, Crystal Structure, and Characterization of Two New Metal Diphosphonates with a 3D Pillared Layered Structure

Two new metal diphosphonates with a 3D pillared layered framework, [Zn2L]center dot 2H(2)O (1) and [Sb(HL)(H2O)]center dot H2O (2) (H4L = H2O3PCH2NC4H8NCH2PO3H2), were synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction as well as IR spectroscopy, elemental analyses, and thermogravimetric analyses. For compound I, each ZnO3N tetrahedron is in turn corner-sharing through three CPO3 tetrahedra from three different phosphonate ligands to form two-dimensional inorganic layers in the ab plane. In compound 2, the inorganic puckered layers are composed of pseudo-octahedral bipyramidal SbO5 and CPO3 tetrahedra in the be plane. The overall structure of both compounds may be described in terms of alternating inorganic infinite layers and organic pillars {-CH2N(C2H4)(2)NCH2-} to form a 3D pillared layered structure.