The Synthesis And Characterization Of N-containing Ligands Modified Polyoxometalates-based Complexs

A series of new inorganic-organic compounds based on polyoxometalates have been synthesized by hydrothermal methods, which choose different kinds of N-containing organic ligands in this paper, and the new compounds have novel structures and potential application. These compounds have been characterized by IR, elemental analyses, UV-vis, TG, X-ray single crystal diffractions and PXRD, and partial compounds have also been investigated by electrochemical, magnetic property and catalysis properties. We also studied the connection of synthesis conditions and structures and many factors may influence the structures, for example, ligands, temperature and p H values.1. Five new polyoxometalate(POM)-templated metal-organic frameworks based on flexible ligands, namely, [Cu6(bip)12(PMoVI12O40)2(PMoVMoVI11O40O2)]·8H2O(1), [Cu6(bip)12(PMoV2MoVI10O40)2(PMoV11MoVIO34)]·8H2O(2), [Ni6(bip)12(PMoVI12O40)(PMoVMoVI11O40)2]Cl·6H2O(3), Cu3(bip)6(PMoV3MoVI9O40)(4), [Co5(H2bib)2(Hbib)2(PW9O34)2(H2O)6]·6H2O(5)(bip=1,3-bis(imidazolyl)propane, bib=1,4-bis(imidazolyl)butane) have been obtained under hydrothermal condition and characterized by single-crystal X-ray diffraction analyses, elemental analyses, and thermogravimetric(TG) analyses. Compounds 1 and 3 represent 3D frameworks, and POMs as the guest molecules are incorporated into the the cages which are composed of the ligands and metals, while compounds 2,4 and 5 show 3D frameworks by hydrogen bonds. In addition, the electrochemical property and the catalytic property of compound 1 have also been investigated.2. Six new inorganic–organic hybrids based on rigid triangular N-containing ligands, Na Cu2(tib)4(H2O)4[H2PWVWVI11O40][H2PWVI12O40]·6H2O(6), Cu3(tib)4Cl4[H2PWVI12O40]2·4H2O(7), Co(tib)2[PWV3WVI9O38]·5H2O(8), Cu3(tib)2[P2MoVI5O22(O2)]·4H2O(9), Mn(pytpy)2MoVI4O13(10), and Co(pytpy)2MoVI4O13(11)(tib=1,3,5-tris(1-imidazolyl)benzene),(pytpy=4’-(4’’-pyridyl)2,4’:6’,4’’-terpyridine) have been hydrothermally synthesized. Single crystal X-ray diffraction studies revealed that compounds 6-9 display two-dimensional(2D) layers structure. In compounds 6-8, the adjacent Keggin anions link with each other by W–O–W to form 1D inorganic chains. Compounds 10-11 are 3D “pillar-layer” frameworks based on bimetal-oxide layers pillared by the pytpy ligands. The compounds have been characterized by elemental analysis, powder X-ray diffraction, X-ray photoelectron spectroscopy and thermogravimetric analysis. Moreover, the electrochemical properties and catalytic properties of compound 6 have also been investigated.3. A series of inorganic-organic hybrid materials based on polyoxometalates(POMs), namely, [M(HL)2(H2O)2][MoVI6O20] [M=Co(12), Ni(13), Cu(14), Zn(15)], [Mn L2(H2O)2][MoVI6O20](16), and(HL)3PMo12O40(17) [L=3–(4-pyridyl)pyrazole], have been synthesized. Single-crystal X-ray diffraction indicate that 12-16 are isostructural. It is worth noting that the polyanions are bridged by Mo-O-Mo to form 1D inorganic chains, which are further connected via M ions to form 2D nets. In compound 17, the ligands are used as the positive ions to balance the charge of the compound. The compounds have been characterized by elemental analysis, powder X-ray diffraction(PXRD) and single-crystal X-ray diffraction. Moreover, the magnetic property of compound 16 has also been investigated in detail.4. A series of inorganic=organic hybrid materials based on polyoxometalates(POMs), namely,(H2bip)2Si W12O40(18);(Hbip)2(H2bip)2(bip)(PMo12O40)2(19);(Hbip1)(H2bip)(PMo12O40)(20);(Hbib)(H2bib)(PMo12O40)·2H2O(21);(H2bib)3(PMo12O40)2(22) and(H4bib2)5(P2MoV4 MoVIO23)2·3H2O(23). Single-crystal X-ray diffraction indicate that the ligands are used as the positive ions to balance the charge of the compounds. The compounds have been characterized by IR, elemental analysis, TG, the electrochemical properties and fluorescent property of compound 18 have also been investigated.