Syntheses, Structures, And Properties Of Polyoxometalate-Based Organic-Inorganic Hybrid Compounds

In the polyoxometalate(POM) chemistry, POM-based organic-inorganc hybrid compounds continue to attract significant attention due to their fascinating structure integrity and interesting redox chemical property. Moreover, the combination of inorganic POM units and metal-organic complex moieties endows the hybrid compounds with favourable properties in light, electricity, catalysis. In such research field, the organic-inorganic hybrid compunds can be divided into two types according to the interaction force between the organic and inorganic components. In type I, the organic and inorganic components are connected by weak forces such as electrostatic attraction, hydrogen bond, intermolecular forces. In type II, the organic and inorganic components are linked by strong covalent bonds.In this thesis, POMs were used as inorganic parts and multidentate O-donor ligand and/or metal-organic complex as organic parts to construct two types of POM-based organic-inorganic hybrid compounds. They are connected by hydrogen bonds with electrostatic attraction and covalent bonds respectively. Furthermore, their crystal structures and properties are also studied.1. A3-D supramolecular framework based on [Co(en)3]2+and [W7O24]6-units were hydrothermally synthesized.[Co(en)3]2[H2W7O24]·8H2O (1)In compound1, a metastable [W7O24]-6anion were isolated in the hydrothermal system, which were further stabilized by the cationic [Co(en)3]2+moieties. Such a hybrid compound shows a3-D supramolecular framework constructed by [Co(en)3]2+and [W7O24]6-units via the extensive H-bonding interactions between cationic [Co(en)3]2+units and the electrostatic attractions between cationic [Co(en)3]2+units and the polyoxoanions. It is interesting that compound1can act as heterogenous photocatalyst to accelerate the photo-degradation reactions of Rh-B under UV irradiation.Compound1represents the first organic-inorganic hybrid compound based on Paratungstate-A.2. Under nitrogen atmosphere, an organic-inorganic hybrid compound [N(C4H9)4]2[V6O13{(OCH2)3CNH-CH2-C16H9}2](2) was prepared.During the preparation of compound2, the precursor [N(C4H9)4]3[H3V10O28] in situ decompose into [V6O19]8". The [V6O19]8-moieties is stabilized by the tris ligands via V-O-C covalent bands. Furthermore, the adjacent Pyrene groups on each hybrid molecules possess strongπ-π interactions, forming a1-D supramolecular chain. It is also noteworthy that the hybrid compound combined the fluorescent groups with negative charge, thus such hybrid materials can be used to combine with the PEC-modified PS microballs so as to apply in virus examination.