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

Abstract

Three new vanadyl gallium phosphates, (H(2)dap)(3)[(VO)(2)(GaO)(2)(PO(4))(4)].H(2)O (1), (H(2)dap)(1.5)[(VO)(2)(GaO)(2)(PO(4))(3)].3H(2)O (2), and (H(2)dap)[(VO)(2)Ga(4)(PO(4))(6)(H(2)O)(4)].2H(2)O (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/V(4+)/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 PO(4) and {V(2)Ga(2)O(14)} cluster which contains a syn-square pyramidal {V(2)O(8)} dimer and two GaO(4) tetrahedra. The tetrameric cluster and V-O-Ga therein are observed in a metal phosphate system. Compound 3 is composed of VO(5)(H(2)O) octahedra, GaO(4)(H(2)O) trigonal bipyramids, and GaO(4) and PO(4) 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 V(4+) and show a T(N) of 12 K for 3. The unusual syn-{V(2)O(8)} dimers in 1 and 2 induce superexchange interactions, while isolated VO(5)(H(2)O) octahedra in 3 display super-super-exchange interaction. Electron paramagnetic resonance spectra with (51)V 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, P1, a = 9.1754(4) A, b = 10.7853(5) A, c = 15.6519(7) A, alpha = 93.251(1) degrees , beta = 92.530(1) degrees , gamma = 95.106(1) degrees , V = 1538.4(1) A(3), and Z = 2; for 2, monoclinic, P2(1)/n, a = 8.9195(3) A, b = 14.6374(5) A, c = 17.8608(6) A, beta = 97.272(1) degrees , V = 2313.1(1) A(3), and Z = 4; and for 3, monoclinic, P2(1)/c, a = 9.0970(5) A, b = 16.9940(9) A, c = 9.6441(5) A, beta = 103.456(3) degrees , V = 1450.0(1) A(3), and Z = 4.