The Study Of Inorganic-organic Hybrid Compounds Based On Keggin-type Polyoxometalates

POM-based inorganic-organic hybrid compounds, especially the Keggin-typeinorganic-organic hybrid compounds, have aroused considerable attention for their numerouspotential applications in diverse areas of research such as biomedicine, nanoscience,photochromism, catalysis, and materials science. In this work, eight new inorganic-organichybrid compounds have been successfully synthesized by using Keggin-typepolyoxometalates as secondary building units （SBUs）, and metal ions as link unit to connectSBUs and organic groups, and characterized by IR spectrum, electrochemical measurements,diffuse reflectance UV-Vis spectrum and single-crystal X-ray diffraction.1A new two-dimensional （2D） inorganic-organic hybrid compoundH₂{[Ni₆（μ3-OH）₃（H₂O）₄（en）（CH₃COO）（IN）(B-PW₉O₃₄)]}·2H₂O （en=ethylenediamine; HIN=isonicotinic acid）（1） has been hydrothermally synthesized and characterized by IRspectrum, electrochemical measurements, diffuse reflectance UV-Vis spectrum andsingle-crystal X-ray diffraction. Compound1contains a nanometer-scale secondary buildingunit （SBU）[Ni₆（μ3-OH）3(B-α-PW₉O₃₄)]₂（{Ni₆PW₉}₂）, in which two {Ni₆PW₉} units arelinked together through Ni–O–W linkages. The adjacent SBUs are connected by IN andforming a2D layer network.1exhibits semiconducting properties with the band gap Egat1.98eV.2A series of3D supramolecular chiral POM-based inorganic-organic hybrid compoundshave been synthesized and characterized by IR spectrum, thermogravimetric analysis, diffusereflectance UV-Vis spectrum and single-crystal X-ray diffraction:H{[M（H₂O）₈]{[Cu（pdc）（H₂O）]₃[SiW₁₂O₄₀]}}·4H₂O （M=La （2）, Pr （3）, Nd （4）, Sm （5）,Eu （6）, Gd （7）, Tb （8））. Single-crystal X-ray diffraction analysis reveals that each Kegginpolyanion is covalently grafted by three [Cu（pdc）（H₂O）] fragments through the interaction ofterminal oxo and Cu. Besides, the compounds have trans（left hands） and cis（right hands）isomer according to the direction of water coordinated to Cu. The isolated earth ion isnine-coordinated with nine water moleculars,which interact with [Cu（pdc）（H₂O）] throughhydrogen bond interaction to obtain the3D supramolecular structure.