Synthesis, Crystal Structure And Vibrational Spectrum Of Inorganic-organic Transition Metal Borate And Vanadate

In this paper, the synthesis of a novel hydrated transition metal tetraborate and two novel inorganic-organic hybrid borate and vanadate were studied. All these crystals have been determined by single crystal X-ray diffraction and further characterized by FT-IR spectrum and Raman spectrum.(1)A novel hydrated transition metal tetraborate NH₄[Co(NH₃)5(H₂O)[B₄O₅(OH)4]2·6H₂O was synthesized. It crystallizes in the orthorhombic system, space group Pnma, a=1.2901(2)nm, b=1.6817(3)nm, c=1.1368(2)nm,α=90°,β=90°,γ=90°, V=2.4742(8) nm³, Z=4, Dc=1.801g/cm³. The single-crystal X-ray diffraction analysis reveals that this compound consists of one distinct coordinated cobalt atom [Co(NH₃)₅(H₂O)]³⁺, [B₄O₅(OH)₄]^2- group, NH₄⁺ group and water molecules. All the units are further connected by hydrogen bonding interactions to form a 3-D framework structure.(2) A novel inorganic-organic hybrid borate [Cu(en)₂B(OH)₃][B₄O₅(OH)₄][B(OH)₃] was synthesized under hydrothermal conditions. It crystallizes in the monoclinic system, space group P2(1)/c, a=1.2779(2)nm, b=1.0166(15)nm, c=1.5019(2)nm,α=90°,β=90.301(2)°,γ=90°, V=1.9396(5)nm³, Z=4, Dc=1.708g/cm³. The single crystal X-ray diffraction analysis gives the existence of [B₄O₅(OH)₄]^2- cluster, [Cu(en)₂B(OH)₃]²⁺ cation and B(OH)3 group in the compound unit. The B(OH)₃ group provides hydrogen bonds to connect all the basic units to construct an interesting framework structure.(3) A novel inorganic-organic hybrid vanadate [Ni₂(py)₅]V₄O₁₂(H₂O)₃ was prepared under hydrothermal conditions. It crystallizes in the orthorhombic system, space group, Pca2(1), a=1.7444(3)nm, b=1.1437(16)nm, c=1.7441(3)nm,α=90°,β=90°,γ=90°,V=3.4797(9)nm³, Z=4, Dc=1.838g/cm3. The single crystal X-ray diffraction analysis reveals four [VO4] distorted tetrahedrons and two differently nickel-centered coordinated distorted octahedrons. All the units are further connected by hydrogen bonds to construct a novel framework structure.(4) The rules of synthesis of hydrated inorganic-organic hybrid borate and vanadate were studied. By analysing the experimental data and condition, a conclusion was made that the appropriate pH is between 8.0 to 9.0 and the appropriate temperature is between 130°C to 140°C when synthesizing hydrated inorganic-organic hybrid borate and vanadate.