Design, Synthesis And Properties Of Polyoxometalate-Based Functional Materials

Polyoxometalates (POMs) are a diverse family of metal-oxygen clusters with unique physical and chemical properties, which can be reliably modified through various techniques and methods to develop sophisticated materials and devices. In parallel with the large number of new crystal structures reported in the literature, the application of these POMs towards multifunctional materials has attracted considerable attention. Functional organic moieties grafted on POMs clusters via covalent bonds, which can build organic-inorganic hybrid materials with unmatched range of structural types and performances. Therefore, it is highly significant to design synthesis and properties of POMs-based functional materials.POMs-based convalent modification has the limiting factors, including methods limited, system modified, the structure and function of the synergistic effect limited. In this paper, feasible methodology has been explored. The modification of the Keggin-based lacancy cluster (K8[a-SiW11039]) through organosilicon form the organic-inorganic hybrid materials. In addition, K7[a-PW11039] instead of K8[a-SiW11039], which expands the synthesis system. The resulting compounds have been characterized by FT-IR,1H (13C,29Si) NMR, ESI-MS, Elemental analysis, TG. It has been provided a feasible passway for the convlent modification of POMs-based functional composites.On the basis of the above research, a novel organic-inorganic hybrid (denoted as Py-SiW11), based on the covalently tethering pyrene moieties onto the mono-lacunary polyoxometalate (POM) cluster of Kg[SiW11O39], has been successfully prepared and characterized by FT-IR,1H (13C,29Si) NMR, ESI-MS, Elemental analysis, TG Considering the fact that pyrene-containing moieties exhibits strong π-π interactions with SWNTs, and POMs could be spontaneously adsorbed onto SWNTs, the properties of the SWNTs/Py-SiW11composite material are depth investigated. The novel SWNTs/Py-SiW11composite has been used as anode material of lithium-ion batteries. The results exhibit high discharge capacities and good cycling stability, which shows the potential for commercial applications.We also successfully synthesize two POMs-based photochromic composites by introduction of azobenzene moiety, which are characterized and confirmed. The isomerization rate and extent of the trans-to-cis POMs-based azobenzene derivatives have been tested by UV-Vis and ’H-NMR.