The First Organic-Templated Vanadyl(IV) Gallophosphates with Ambient ⁵¹V Hyperfine Structure, {V₂Ga₂O₁₄} Cluster or Heterometal 12-Ring Channels

Three new vanadyl gallium phosphates, (H2dap)3[(VO)2(GaO)2(PO4)4]·H2O (1), (H2dap)1.5[(VO)2(GaO)2(PO4)3]·3H2O (2), and (H2dap)[(VO)2Ga4(PO4)6(H2O)4]·2H2O (3) (dap = 1,3-diaminopropane), have been prepared under mild solvothermal conditions and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, magnetic susceptibility, and EPR spectroscopy. They are the first examples of an organic/V4+/Ga/P/O system that displays three different dimensional structures with a common template. The 1D chain structure of 1 and the 2D layered 2 are both built up with a PO4 and {V2Ga2O14} cluster which contains a syn-square pyramidal {V2O8} dimer and two GaO4 tetrahedra. The tetrameric cluster and V−O−Ga therein are observed in a metal phosphate system. Compound 3 is composed of VO5(H2O) octahedra, GaO4(H2O) trigonal bipyramids, and GaO4 and PO4 tetrahedra from which a unique 3D structure containing one-dimensional 12-ring channels is constructed. The channel aperture uncommonly comprises heterometal (V, Ga) polyhedra. Magnetic susceptibility data for 1−3 are consistent with V4+ and show a TN of 12 K for 3. The unusual syn-{V2O8} dimers in 1 and 2 induce superexchange interactions, while isolated VO5(H2O) octahedra in 3 display super-super-exchange interaction. Electron paramagnetic resonance spectra with 51V hyperfine structures were distinctly observed at 300 K for 1, while they started emerging at 30 K for 2 and 7 K for 3. The average hyperfine constant, 85.56 Gauss, was obtained via spectral simulations and nonlinear least-squares fittings for 1 and 2. Crystal data for 1 are triclinic, P1̅, a = 9.1754(4) Å, b = 10.7853(5) Å, c = 15.6519(7) Å, α = 93.251(1)°, β = 92.530(1)°, γ = 95.106(1)°, V = 1538.4(1) Å3, and Z = 2; for 2, monoclinic, P21/n, a = 8.9195(3) Å, b = 14.6374(5) Å, c = 17.8608(6) Å, β = 97.272(1)°, V = 2313.1(1) Å3, and Z = 4; and for 3, monoclinic, P21/c, a = 9.0970(5) Å, b = 16.9940(9) Å, c = 9.6441(5) Å, β = 103.456(3)°, V = 1450.0(1) Å3, and Z = 4.