The Study Of Transition-metals Derivatives Based On Polyoxotungstates Containing Heteroatoms With A Lone Pair Of Electrons

In this thesis, we use hydrothermal synthesis, trivacant [B–α–SbW9O33]9– and [B–α–BiW9O33]9– polyoxoanions as POM precursors by the linking of transition metals and transition metal coordination complexes. We have successfully synthesized four new polyoxometalates, and study the synthetic conditions and rules of these compounds. The four compounds were structurally characterized by elemental analyses, TG, XRD, IR and single crystal X-ray diffractions. The electrochemical properties of these compounds have been studied.1. Compounds 1 and 2 are two novel sandwich-type (Krebs–type) polyoxotungstate compounds with the formulas: [enH2]5[CuII(en)2][CuI2(WO2)2(β–SbW9O33)2]·16H2O(1) [enH2]5[CuII(en)2][CuI2(WO2)2(β–BiW9O33)2]·22H2O (2).Compounds 1 and 2 are isomorphic, which are composed of two trivacant [B–β–XW9O33]9- (X = SbIII (1), BiIII (2)) subunits joined together by two Cu(I) ions and two W(Ⅵ) ions resulting in two novel Krebs–type sandwich structures. These polyoxoanions are further connected by Cu(I) ions and [CuII(en)2]2+ coordination cations, and afford the first copper(I)–linked 2D layer structure constructed from Krebs–type polyoxotungstates. Additionally, the electrochemical behavior and electrocatalysis of 1 and 2 modified carbon paste electrodes (CPEs) have been studied. The results indicate that they have good electrocatalytic activities for the reduction of nitrite.2. Compounds 3 and 4 are tungstoantimonates containing Dawson–like [SbW18O60]9– polyoxoanions with the formulas: [H2bpy]2[Ni(bpy)(Hbpy)2HSbW18O60]·4H2O (3) [H2bpy]2[Cu(bpy)(Hbpy)2HSbW18O60]·5H2O (4).Compounds 3 and 4 are isomorphic, in which non–classical Dawson–like [SbW18O60]9– polyoxoanions are used as bidendate ligands to covalently link two adjacent 1D coordination cationic chains([Ni(bpy)(Hbpy)2]n4n+ for 3 or [Cu(bpy) (Hbpy)2]n4n+ for 4), affording the first 3D frameworks composed of Dawson–like [SbW18O60]9– polyoxoanions. Furthermore, the compound 4–modified carbon paste electrode (4–CPE) displays good electrocatalytic activity for the reduction of nitrite.