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Keywords:

aluminum phosphate, gallium phosphates, open-framework solid, Science & Technology, Physical Sciences, Chemistry, Inorganic & Nuclear, Chemistry, Physical, Physics, Condensed Matter, Chemistry, Physics, HYDROTHERMAL SYNTHESIS, FRAMEWORK, ALUMINOPHOSPHATE, CHANNELS, 4TREN, 0204 Condensed Matter Physics, 0302 Inorganic Chemistry, 0303 Macromolecular and Materials Chemistry, Inorganic & Nuclear Chemistry, Materials, 3402 Inorganic chemistry, 5104 Condensed matter physics

Abstract:

The mixed metal(II)-aluminum phosphates M3Al6(PO 4)12ṡ4trenṡ17H2O (M=Mg 2+,Mn2+,Co2+) and its gallium phosphate analogs M3′Ga6(PO4)12ṡ4trenṡ17H 2O (M′=Mg2+,Mn2+,Fe2+,Co 2+,Zn2+) have been hydrothermally synthesized with the tris(2-aminoethyl)amine (tren) as a structure-directing agent (453 K, 36 hours, autogenous pressure). The solids were characterized by single-crystal X-ray diffraction. Their crystal structures are cubic, a≈16.8 Å and may be described in I-43m. The open-framework is built up from an enneameric unit (T=Al or Ga / Mg, Mn, Fe, Co, Zn) containing five TO4 and four PO4 tetrahedra (one of the PO bonding is terminal). A central TO4 tetrahedral unit shares all the corners with four phosphate groups. Two phosphate groups are connected to two other peripheral TO4 units. It results in the formation of a "pseudo" planar building block T5P4 consisting of four square 4-rings. The connection of the T5P4 units generates a three-dimensional framework, which defines a super-sodalite topology. The resulting cavities (diameter of 10 Å) are bound by 12-ring windows in which are located the tren species in interaction with the phosphate groups (mainly terminal PO bonding) through hydrogen bond. A (H2O)17 cluster is encapsulated in the super-sodalite cages. The TO distances are discussed according to the ionic radii of the trivalent cations (Al, Ga) and the different divalent cations (Mg, Mn, Fe, Co, Zn). © 2006 Elsevier SAS. All rights reserved.