Amine-Templated Unidimensional Phosphate−Diphosphates of Gallium and Vanadium, [NH₃CH₂CH₂NH₃][M(H₂PO₄)(P₂O₇)] (M = Ga, V)

A new one-dimensional gallium phosphate−diphosphate, [C₂H₁₀N₂][Ga(H₂PO₄)(P₂O₇)], has been synthesized under solvothermal conditions at 433 K in the presence of ethylenediamine, and the structure was determined using room-temperature single-crystal X-ray diffraction data (M_r = 402.76, monoclinic, space group Cc, a = 8.6139(4), b = 14.929(1), and c = 9.3109(4) Å, and β = 106.541(4)°; V = 1147.8 ų, Z = 4, R = 4.39%, and R_w = 5.03% for 2049 observed data (I > 3(σ(I))). The structure consists of anionic chains of formula [Ga(H₂PO₄)(P₂O₇)]^2- containing GaO₆ octahedra linked by PO₂(OH)₂ and P₂O₇ units, which are charge-balanced by ethylenediamine dications. The chains are held together by a network of hydrogen bonds involving both interchain and chain−diamine interactions. Polycrystalline samples of the isostructural vanadium and mixed vanadium−gallium analogues, [C₂H₁₀N₂][V(H₂PO₄)(P₂O₇)] and [C₂H₁₀N₂][[V_xGa_1-x(H₂PO₄)(P₂O₇)] (x ∼ 0.65), have also been prepared. The former has an effective magnetic moment of 2.70(1) μ_B per vanadium cation consistent with the presence of V³⁺ ions in an octahedral environment.