New Titanium and Nickel Gallophosphates with Layered Structures

Abstract

Two new transition-metal gallophosphates, (H(2)C(4)H(10)N(2))(3)[(Ti(2.5)(H(2)O)(4)Ga(5.5)(PO(4))(10)].2H(2)O (TGP-1) and [H(3.5)(C(4)H(13)N(3))(2)][(Ni(0.5)(OH)(4)Ga(5.5)(PO(4))(3)(HPO(4))(4)].2H(2)O (NGP-1), have been synthesized under mild hydrothermal conditions and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, electron paramagnetic resonance, electron probe microanalysis, and magnetic susceptibility data. TGP-1 exhibits a unique two-dimensional structure consisting of tetrahedral and octahedral metals centers and is the foremost paramagnetic TiGaPO material ever prepared. NGP-1 as well represents the first NiGaPO compound and adopts a layer structure that is constructed from hexameric M-O clusters of trigonal bipyramids and octahedra. In both compounds, the transition metals incorporate with gallium into octahedral sites only, while the four- and five-coordinated metals centers are only Ga(3+) ions. The unique sites for Ti(3+) and Ni(2+) ions have been initially elucidated from single-crystal structure refinements and further confirmed by bond-valence-sum calculations, EPR, and magnetic susceptibility studies. Crystal data: TGP-1, monoclinic, P2(1)/c; a = 25.692(2) A, b = 9.6552(8) A, c = 9.8418(8) A, beta = 96.737(2)(o) , V = 2424.5(3) A(3), and Z = 2; NGP-1, monoclinic, C2/c, a = 20.8363(12) A, b = 11.9546(7) A, c = 16.4577(9) A, beta = 117.285(1)(o) , V = 3643.3(1) A(3), Z = 4.