Hydrothermal Synthesis and Structures of Three-Dimensional Zinc Phosphates Built-Up from Two-Dimensional Layers and One-Dimensional Chains and Ladders

Three new zinc phosphates, I, [(NH₄)(CH₃CH₂CH₂NH₃)][Zn₃(HPO₄)(PO₄)₂]; II, [NH₃(CH₂)₃NH(CH₂)₃NH₃][Zn₃(H₂PO₄)(HPO₄)₂(PO₄)]·H₂O; and III, [NH₃(CH₂)₃NH₂(CH₂)₃NH₃][Zn₃(HPO₄)₃(PO₄)], have been synthesized in the presence of 1,3,5-triethylhexahydrotriazine (TEHT) and dipropylenetriamine (DPTA), and their structures have been determined by single-crystal X-ray diffraction. The structures consist of vertex-linking ZnO₄ and PO₄ tetrahedral units forming channels bound by 8-, 10-, and 16-T atoms (T = Zn, P). While the structures of I and II are built up from two-dimensional layers cross-linked by one-dimensional ladders or chains, that of III is built up by cross-linking of ladders. The framework structure of II and III is built up from strictly alternating ZnO₄ and PO₄ units, and in I, infinite Zn−O−Zn chains are observed, formed by two Zn atoms sharing two three-coordinated oxygen atoms. The amine molecule in I, propylamine, has been obtained by the decomposition of TEHT under hydrothermal conditions. The amine molecules in I−III occupy the channels. Crystal data:  I, triclinic, space group = P(−1) (no. 2), M = 559.18, a = 5.0986(6) Å, b = 10.4943(1) Å, c = 12.4457(1) Å, α = 87.614(2)°, β = 87.258(1)°, γ = 89.994(2)°, V = 664.6(1) ų, R₁ = 0.0342, wR₂ = 0.091 [1913 observed reflections with I > 2σ(I)]; II, triclinic, space group = P(−1) (no. 2), M = 731.28, a = 8.4821(7) Å, b = 9.1326(8) Å, c = 14.7961(1) Å, α = 90.382(2)°, β = 100.123(2)°, γ = 107.04(1)°, V = 1076.7(1) ų, R₁ = 0.0332, wR₂ = 0.0747 [2954 observed reflections with I > 2σ(I)] III, monoclinic, space group = Cc (no. 7), M = 713.26, a = 15.1085(4) Å, b = 8.8403(4) Å, c = 17.2628(6) Å, β = 114.537(2)°, V = 2097.5(1) ų, R₁ = 0.0315, wR₂ = 0.0804 [2323 observed reflections with I > 2σ(I)].