Novel Open-Framework Tin(II) Phosphate Materials Containing Sn−O−Sn Linkages and Three-Coordinated Oxygens

Two new open-framework tin(II) phosphate materials have been synthesized hydrothermally and their structures elucidated by single-crystal X-ray diffraction. These materials exhibit an entirely new building motif, unknown in phosphate-based materials, viz., vertex-sharing truncated square-pyramidal SnO4 units, in addition to the trigonal-pyramidal SnO3 units. The connectivity between the SnO3, SnO4, and PO4 units is such that Sn−O−Sn linkages are observed for the first time. The networking creates three-coordinated oxygens in the structure. Crystal data for compound I, [Sn3(PO4)2(OH)]-·0.5[(NH3)(CH2)6(NH3)]+: monoclinic, a = 9.315(2) Å, b = 16.806(1) Å, c = 9.513(3) Å, β = 111.03(1)°, V = 1390.0(5), Z = 4, M = 622.13(1), Dcalc = 2.973 g cm-3, Mo Kα, RF = 0.039. Crystal data for compound II, [Sn3(PO4)2(OH)]-·0.5[(NH3)(CH2)8(NH3)]+: orthorhombic, a = 10.390(1) Å, b = 16.087(1) Å, c = 18.717(1) Å, V = 2849.3(1), Z = 4, M = 636.16(1), Dcalc = 2.595 g cm-3, Mo Kα, RF = 0.07.