Syntheses And Structures Characterizations Of Tungsten And Molybdenum-Vanadium Metal-oxygen Clusters

In this thesis, we use a series of simple polyoxometalates or oxides, select transition metal and organic ligands with appropriate space hindrance, by hydrothermal synthesis method to build a series of polyoxometalates with novel structures and excellent properties. The structures of all compounds have been characterized by X-ray diffraction analyses, elemental analyses IR spectra, UV-Vis, XPS spectra, XRD, TG and the fluorescence properties. In this thesis, eight new polyoxometalates were synthesized for the first time.Ⅰ. Tungsten oxygen clustersBy the hydrothermal synthesis technology, we synthesized six Tungsten oxygen clusters.[BW12O40]2[Cu2(Phen)4Cl](H24,4’-bpy)4·H3O·5H2O;[HPW12O40][Cd2(Phen)4Cl2](4,4’-bpy)2;[SiW12O40]1.5[Cu(4,4’-bpy)3.5]·(H24,4’-bpy)·3H3O3;[PW12O40][CuCl(1,10-Phen)(H2O)][4,4’-H2bpy]·1.5H2O4; An unusual feature of1is that it contains a metal halide cluster[Cu2(Phen)4Cl]+, which is composed of two[Cu(1)(Phen)2]+transition metal coordination complexes (TMCs) and one chloride ion located at the special position with the occupancy factor of0.5.The chloride ion serves as an inorganic bridge joining the two [Cu(1)(Phen)2]+TMCs into a metal-chloride-ligand coordination complex. Compound2contains a [Cd2(Phen)4Cl2]2+metal halide cluster, which is composed of two [Cd(Phen)2]2+TMCs and two chloride ions. The chloride ion adopts a V-shaped coordination geometry. And serve as inorganic bridges joining the two [Cd(Phen)2]2+TMCs into a novel metal chloride cluster. Compound1and compound2are not common hybrids based on polyoxometalates and metal halide clusters, they also contain dissociated organic ligands. The compound3exists two different configurations of the [SiW12O40]4-anion: POM A and POM B. the anion of POM A exhibits the typical Keggin configuration. In contrast to POM A, the POM B in compound3shows the typical Pseudo-Keggin configuration. The chain constructed by the TMCs and the POMs in compound4can be described as a train structure with each POM as the railroad car. The hydrogen bond attached4,4-bpy just looks like a waving flag attached on each railroad car, when the train is running along the-a axis.Ⅱ. Molybdenum-Vanadium oxygen clustersWe synthesized two Molybdenum-Vanadium oxygen clusters,[PMo12V2O42][Cd2(Phen)2(4,4’-bpy)2(H2O)2(C2O4)]·2H2O5[PMO12V2O42][Cu2(4,4’-bpy)2][Cu2(Phen)(4,4’-bpy)2]·3H2O6, The asymmetric unit of5and6are both composed of [PMO12V2O42]4-, the CTMC [Cd2(Phen)2(4,4’-bpy)2(H2O)2(C2O4)]2+in5is constructed from two Cd coordination complexes connected by an oxalate ions. Each Cd ion exhibits a distorted cis-octahedral geometry through bonding to three nitrogen atoms from one4,4’-bpy ligand and one chelate Phen ligand and three oxygen atoms from one water molecule and one chelate oxalate ion. There is a novel2-D framework structure in6. And the framework is constructed from copper ions, bpy ligand and POMs connected together with POM-M-L-M-POM linking fashion.