Synthesis And Properties Research Of The Polyoxometalates Contained Molybdenum Atom

Polyoxometalates（POMs） are consist of cations and polyanion clusters, as their diversiform and new structural characteristics,POMs in many fields have a wild range of applications.In the paper,under hydrothermal condition,have been synthesis six novel Keggin-type polyoxometalates based on {PMo12} and three isopolyoxometallates containing molybdenum atom.Above nine compounds have been characterized by elemental analysis, TG, IR, UV, XRD and single-crystal X-ray diffraction, meanwhile, their electrochemical properties, electrocatalytic properties, photocatalytic properties or adsorption properties have been investigated.Precursor method synthesis compound 1 and 2 based on {PMo12}:（H₂pyttz）[Cd（H₂pyttz）2（H₃pyttz）]（PMo12O40）2（1）H₃O[Mo6（bpy）₆O₁₇][PMo12O40]·2H₂O（2）（H₂pyttz=（3-（pyrid-4-yl）-5（1H-1,2,4-triazol-3-yl）-1,2,4-trizolyl）;bpy=2,2′- bipyridine）Single-crystal X-ray diffraction studies reveals that compound 1 is consist of two {PMo12}, a single H₂ pyttz and a “windmill”structure containing Cd2+ and three H₂ pttz.Compound 1 formed a one-dimensional chain,two-dimensional layer and three-dimensional structure via supramolecular interaction.Compound 2 combines [Mo6O₁₇（bpy）₆]2+chain formed by bpy ligand with [PMo12O40]3-cluster,as to one-dimensional chain via supramolecular interaction.Along ac plane, adjacent 1D chains as ABAB mode formed 2D layer, anions locate in the adjacent 2D layer via supramolecular interaction, the host cation layers and Keggin ions layers alternately array together to form unique sandwich-type supramolecular networks.One-step method synthesis Compound 3⁶ based on {PMo12}:[{Cu（H₂O）（H₂pyttz）}{Cu2（H₂pyttz）}（PMo12O40）]2（3）[（H₂bib-I）（Hbib-I）（PMo12O40）]（4）[H₃O（H₂bib-II）（PMo12O40） ]（5）[（H₂bia）（Hbia）（PMo12O40）]（6）(H₂pyttz=（3-（pyrid-4-yl）-5（1H-1,2,4-triazol-3-yl）-1,2,4- trizolyl）; bib-I=(1,3-bis（imidazol-1-ylmethyl）benzene;bib-II=（1,4-bis（imidazol-1-ylmethyl）benzene;bia=1,3-bis（imidazolyl）aniline）Single-crystal X-ray diffraction studies reveals that compund 3 is a copper-carbon carbene dimer formed by a unit of three Cu+,H₂ O and three H₂ pyttz.The dimer arrange and stack a one-dimensional chain,two-dimensional layer and three-dimensional structure via supramolecular interaction.The modified ligand compound 4 and compound 5 is isomeride, so their molecular configuration are basically similar,the difference is only the number of ligand beside {PMo12}.Compound 4 constitutes a 1D chain like a“curb chain”via supramolecular interaction, and then formed 2D,3D structure.Compound 5 has two different connect ways as C-O bond distance diverse arrange,as the two-dimensional A and B cross stacked neatly arranged to form a diamond-shaped three-dimensional structure.Compound 6 is a supramolecular composed of [PMo12O40]3-cluster and two bia ligands.The modified ligand bia is obtained by imidazoly group from tib in-situ synthesis to amino group（tib=1,3,5-tris（1-imidazoly）benzene）.The 1D chain via supramolecular interaction formed 2D layer by staggered arrangement,come to 3D structure.One-step method synthesis pure inorganic compound 7⁹ baesd on {Mo₄O₁₃}:Ba Mo₄O₁₃·2H₂O（7）Ba Mo₄O₁₃·2H₂O（8）Sr Mo₄O₁₃·2H₂O（9）Single-crystal X-ray diffraction studies reveals that compounds 7 and 8 are isomers, and compounds 9 is isomorphic with compound 7⁸,only the alkaline earth metal ions are different.The compounds 7⁹ form high-dimensional compounds connect with Mo-O bonds,the main structures is consist of Mo O6 and Mo O5 groups.Additionally, their electrochemical properties, electrocatalytic properties and photocatalytic properties of Rhodamine-B（Rh B） at room temperature have been investigated.Under UV irradiation, the degradation rate of Rhodamine B of compounds 2⁹ can reach more than 90%, indicating that have good photocatalytic activity.Compound 1 also carried out on the adsorption tests in the dark, the research shows that compound 1 adsorb the methylene blue and rhodamine B solution have very good effect.The adsorption rate of Rh B and MB are 98.25% and 96.63%, so the compound 1 can be used to dye adsorption separation.