Assembly Chemistry Of Polyoxometalates Modified By Transition Metal-tetrazole/Imidazole Derivative Ligands

A series of hybrids based on different POMs have been obtained in this thesis, whichare modified by transition metals (Cu2+/Cu+?Ag+?Ni2+?Co2+) and tetrazole/imidazoleligands, respectively. The influences of polyoxoanions, reaction conditions, configurationsand functional groups of ligands on the structures have been investigated. Further, someproperties of the hybrids have been studied, and the relationships between properties andstructures for the hybrids have been also analyzed.Seventeen POM-based hybrids modified transition metals and tetrazole/imidazoleligands have been obtained by hydrothermal methods, which have been characterized by IR,TG, single crystal X-ray diffractions, PXRD, XPS, etc. The electrochemical properties,magnetic properties, photoluminescence properties of these hybrids have been studied.1. Keggin (Wells-Dawson) POM derivatives modified by Ag/tetrazole ligandsFour novel POM-based hybrids have been synthesized in same Ag/4-ptz reactionsystem by introducing different polyoxoanions (SiW12or P2W18), or by altering thefunctional groups of tetrazolate ligands in the same Ag/PMo12reaction system.[Ag7(4-ptz)5(H2SiW12O40)(H2O)](1)[Ag10(4-ptz)5(HP2W18O62)(H2O)4]�2H2O (2)[Ag7(L1)4(H2O)(PMo12O40)](3)[Ag5(L2)2(PMo12O40)]�H2O (4)In compound1, the4-ptz ligand exhibits varieties of connection modes. A doubleKeggin anion-templated nanocage with the dimension of21.89�13.91�12.07isobtained in the3D framework structure. In same Ag/4-ptz reaction system, a2D layer isconstructed by ��shield-like'' metal-organic circles templated by P2W18polyoxoanions incompound2, which is extended to a3D structure by covalent bonds in an interdigital mode.The polyoxoanions play key roles in the process of assembly. Compounds3and4areobtained in the same Ag/PMo12reaction system, except for the different functional groupsof tetrazolate ligands. In compound3, a beautiful POM-inserted2D network is formed bypolyoxoanions and {Ag6(L1)4}nchains constructed from hexa-nuclear subunits, which arelinked to each other through covalent bonds into a (6,6,10)-connected3D framework. The3D framework of compound4is constructed from chains of circle-connecting-circle anddimeric polyoxoanions. The different structural features of the two compounds suggest thatthe functional groups of tetrazolate ligands should play a key role in constructing theframeworks.2. POM derivatives modified by Cu/tetrazole ligandsFour POM-based hybrid compounds have been obtained in the Cu/(4/2-ptz) reaction system by altering polyoxoanions or reaction conditions.Cu9(?2-OH)4(?3-OH)2(H2O)8(4-Hptz)8(P2W18O62)2�30H2O (5)Cu9(?2-OH)6(H2O)6(2-ptz)6[P2W18O62]�6H2O (6)Cu3(H2O)8(2-ptz)2[?-Mo8O26]�2H2O (7)Ag2[Cu(2-ptz)2][?-Mo8O26]0.5�H2O (8)In compound5, a novel nonanuclear copper cluster is constructed from twotetranuclear {Cu4(?2-OH)(?3-OH)(4-Hptz)3}6+moieties, linked to each other though oneCu4ion with the aid of two ?2-OH and two4-ptz ligands. Then the P2W18polyoxoanionsbridge the nonanuclear copper clusters into a1D ladder-like chain. In compound6, a1Dchain is formed by {Cu3(?2-OH)(2-ptz)} moieties, which is linked into a3D frameworkstructure by P2W18polyoxoainons. The configurations of the ligands may result in thedifferent structures of compounds5and6. When the P2W18polyoxoanion is replaced byMo8anion in the same Cu/2-ptz system, compound7displays a POM-based2D layer builtby1D {Cu2(2-ptz)2(Mo8)}nchains linked by Cu2+ions. Compound8is a POM-based hybridconstructed from3d/4d mixed metals.3. POM derivatives modified by thiabendazole metal/tbz polymersSeven POM-based hybrids have been hydrothermally synthesized composed of M/tbz(M=CuI, NiII, CoII) segments.[CuI2(tbz)2][CuI(tbz)2(PMoVI10MoV2O40CuI2)](9)[CuI3(tbz)4](PW12O40)�2H2O (10)[CuI2(tbz)3]2(PMoVI11MoVO40)�2H2O (11)[CuI2(tbz)3]2(SiMo12O40)�2H2O (12)[CuI2(tbz)3][CuI(tbz)2](PW12O40)(13)[NiII(tbz)2](V2O6)(14)[CoII(tbz)2](V2O6)(15)Compound9exhibits a3D supramolecular framework with2D channels, constructedfrom a novel cap-to-cap {CuI(tbz)2(PMoVI10MoV2O40CuI2)}n2chain via hydrogen bondingand ?�? interactions, in which {CuI2(tbz)2}2+segments are incorporated. In compound10,the PW12polyoxoanion is modified by two {CuI1.5(tbz)2}1.5+segments to form a bisupportedanion. Compounds11-13are composed of discrete polyoxoanions and Cu+/tbz segments. Incompounds14and15, the butterfly-like {M(tbz)2}2+(M=NiII?CoII) segments are grafted ona {V2O6}n2-chain to construct another1D butterfly-like chain along c axis. The resultsindicate that the polyoxoanions and configurations of tbz ligand play key roles in theself-assembly processes.4. POM derivatives modified by Cu/star-like ligand Two hybrid compounds based on POMs have been synthesized composed of star-likeligand copper polymers.[CuII3(H2O)5(tib)2(P2Mo5O23)]�2H2O (16)[CuI2(Htib)2(PMoVI11MoVO40)]�H2O (17)In compound16, a2D wave-like layer is constructed from concave belts bridged byP2Mo5polyoxoanions in a ��hand-in-hand'' mode. Compound17shows a1D ladder-likechain formed by {Cu(tib)}n+chains acting as two sides of the ladder and PMo12anionsacting as middle rails.