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, [Zn 2 L ] · 2H 2 O ( 1 ) and [Sb(H L )(H 2 O)] · H 2 O ( 2 ) (H 4 L = H 2 O 3 PCH 2 NC 4 H 8 NCH 2 PO 3 H 2 ), 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 1 , each ZnO 3 N tetrahedron is in turn corner‐sharing through three CPO 3 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 SbO 5 and CPO 3 tetrahedra in the bc plane. The overall structure of both compounds may be described in terms of alternating inorganic infinite layers and organic pillars{–CH 2 N(C 2 H 4 ) 2 NCH 2 –} to form a 3D pillared layered structure.