Synthesis And Properties Of Inorganic-organic Hybrid Compounds Based On Keggin-type Heteropolytungstates

Lacunary polyoxometalates as an important family of polyoxometalates?POMs?,have been regarded as one kind of outstanding inorganic building blocks for the design and synthesis of inorganic-organic hybrid compounds due to the coordination ability of the numerous external oxygen atoms,nanometer-sized and an unmatched range of physical and chemical properties.The excellent performance units can be obtioned by introducing one or more functional ions in the vacancy of lacunary POMs.On this bases,inorganic-organic hybrid compounds with a variety of structural motifs and interesting properties can be designed by the modification of metal complexes or organic functional groups,which should lead to new functional materials.In this paper,sixteen novel inorganic-organic hybrid compounds 1-16 have been synthesized by lacunary POMs {PW11},{PW9} and {SbW9} as precursors,which have been structurally characterized by IR,UV-vis,elemental analysis,XRPD and single-crystal X-ray diffraction.Moreover,the luminescent spectroscopy,magnetic properties and electrochemical behaviors have also been investigated in detail.This paper has divided into three chapters which were introduced as follows:1.Five novel inorganic-organic hybric compounds 1-5 have been prepared under hydrothermal conditions by the reaction of {PW11V},pyridine-2,6-dicarboxylate?L1?and Ln?NO3?3?Ln = Eu,Sm,Nd,Pr,Dy?.H₃[Eu3?L1?4?H₂O?20?PW11VO40?·4H₂O?1?H₃[Sm3?L1?4?H₂O?20?PW11VO40?]·4H₂O?2?[Nd4?L1?4?H₂O?12?PW11VO40?]·8H₂O?3?[Pr4?L1?4?H₂O?12?PWI11VO40?]·8H₂O?4?[Dy4?L1?4?H₂O?12?PW11VO40?]·8H₂O?5?Compounds 1-5 display 3D structure in which {PW11V} units occupying the channels of the cationic framework based on Ln-L1.Compounds 1-3 and 5 give strong luminescent emissions in the solid state at room temperature.The magnetic properties of compounds 1-4 and compound 5 have been studied,indicating antiferromagnetic and ferromagnetic interactions between metal atoms,respectively.Three novel inorganic-organic hybric compounds 6-8 have been prepared by using the {PW9V3}instead of the {PW11V}.H4[Nd3K?L1?4?H₂O?16?PW9V3O40?]·2H₂O?6?H4[Sm3K?L1?4?H₂O?16?PW9V3O40?]·2H₂O?7?H4[Pr3K?L1?4?H₂O?,6?PW9V3O40?]·2H₂O?8?Compounds 6-8 display 3D structure in which {PW9V3} units link to the cationic framework through K atoms.The UV-vis spectra,luminescence properties and magnetic properties for 6-8 have been studied.2.Five novel inorganic-organic hybric compounds 9-13 have been prepared under hydrothermal conditions by the reaction of {PW9V3},Ln?N03?3?Ln=Eu-9,Tb-10,Dy-11,Sm-12,Pr-13?and two different organic ligands,1,4-bis?pyridinil-4-carboxylato?-1,4-dimethylbenzene?L2??9-11?and 1,4-bis?pyridinil-3-carboxylato?-1,4-dimethylbenzene?L3??12-13?.[Eu2?H₂O?10?L2?3PW9V3O40]·2H₂O?9?[Tb2?H₂O?10?L2?3PW9V3O40]·2H₂O?10?[Dy2?H₂O?10?L2?3PW9V3O40]·2H₂O?11?[Sm2?H₂O?10?L3?3PW9V3O40]·2H₂O?12?[Pr2?H₂O?10?L3?3PW9V3O40]·2H₂O?13?Compounds 9-13 display 1D chain structure.The optical properties imply the energy bands?Eg?of compounds 9-13 are 2.08,2.15,2.10,2.11 and 2.05 eV,respectively,implying that compounds 9-13 are with narrow band-gap semiconductor properties.The magnetic behaviors of 9 and 12 suggest the presence of antiferro-magnetic coupling interactions between rare earth metal centers,while 10 represents the ferro-magnetic coupling interactions.3.We select the trivacant heteropolyanion[a-SbW9O33]9-as precursor,synthesizing three novel transition-metal substituted compounds:H5?C6NO2H4?2[Fe4Na2?H₂0?18?B-?-SbW9O33?2]-8H₂O?14?H₂Cu2?H₂O??1,2-dap?[Cu?1,2-dap?W12O40]·H₂O?15?H4[Na8?H₂O?12Cu3?H₂O?2?SbW9O33?2·2H₂O?16?Compound 14 represent the one-dimensional chain based on sandwich-typt dimers through Na double bridges,in witch the dimer is constructed from two equivalent trivacant Keggin[a-SbWO33]9-subunits sandwiching a tetra-Fe subsituted sandwich-type units.Compound 15 shows an isolated structure in which?H₂W12O40?6-units are connected with the copper complexes.Compound 16 represent the 3D structure based on sandwich-typt dimers through Na bridges,in which the sandwich-typt dimer is constructed from two Keggin[a-SbW9O33]9-subunits sandwiching a hexagonal metal cluster.The optical properties imply the energy bands?Eg?of compounds 14-16 are 2.96,2.48 and 3.15 eV,respectively,implying that compounds 14-16 are with narrow band-gap semiconductor properties.Magnetic measurements indicate that compounds 14-16 display the week antiferromagnetic exchange interactions.Compound 14 has a catalytic activity on the oxidation of alkenes.