Syntheses, Structures And Properties Of Molybdenum(Tungsen)-(Vanadium)-oxygen Clusters

This thesis mainly focused on the syntheses, structures and properties ofMolybdenum(tungsen)-(vanadium)-oxygen clusters. Eleven new non-classicalmetal-oxygen clusters with novel structure and excellent properties have beensynthesized hydrothermally under acid or weak alkaline condition and chooseddifferent reaction system. The eleven compounds were all synthesized for the firsttime. They are as follows:[Cu(imz)2][Cu(phen)(imz)]2{[Cu(phen)]2[PMo12V2O42]}(1)[Co2(2,2-bpy)4(C2O4)][Co(2,2-bpy)3][PMo12V2O42](2,2-bpy)0.5·H2O (2)[Cu(en)2][Cu(en)2(H2O)]2[SiMo8V6O42][Cu(en)2]·1.5H2O (3)[Cu(en)2(H2O)]{[Cu0.5(en)]3[W9.5V5.5O42Cu(en)2]}·3.5H2O (4)[Ni(en)2]{[Ni(en)2]2[Mo8V8O40(SiO4)]}(dien)2H2O (5)[Ni(en)2]{[Ni(en)2]2[Mo8V8O40(VO4)]}(en) H2O (6)[Cu(en)2]2[W6.5V10.5O44{Cu(en)2(H2O)}2]3H2O (7)(H24,4-bpy){[Cu(4,4-bpy)]2[SiW12O40]}(8)(H24,4-bpy)2(H4,4-bpy)[SiW12O40]·4H2O (9)(H24,4-bpy)2[SiW12O40]·2H2O (10)(H24,4-bpy)(H4,4-bpy)[PMo12O40](11)The transition metals, reaction system pH value and organic ligands on theinfluence of the reaction products were studied. The compounds have beencharacterized by single crystal X-ray diffraction analyses elemental analyses, infraredspectroscopy(IR), UV-vis, X-ray diffraction analyses(XRD), X-ray photoelectron spectroscopy(XPS), electron paramagnetic resonance(EPR) spectra andthermogravimetric(TG) analyses. The photocatalytic activity, magnetism performanceand electrochemistry performance of some compounds have been studied, whichwould play an important role in the explorations of special properties and structuresfor the compounds.1. bis-capped Keggin molybdenum(tungsen)-(vanadium)-oxygen clustersApplying in hydrothermal synthesis reactions, we synthesized four bis-cappedKeggin molybdenum(tungsen)-(vanadium)-oxygen clusters (compounds1-4).Compound1is an example based on bis-vanadium-capped Kegginmolybdenum-vanadium polyoxoanion bis-supported transition metal complex viaterminal-and bridge-oxygen atoms. The most unusual structural feature of compound1is that there are three different types of copper cations in compound1. And forminga novel3-D supramolecular framework via π···π stacking and hydrothermal bondinginteractions. Compound2with discrete structure based on {PMo12V2O42}polyoxoanions and different transition-metal coordination fragments. Compound2isthe first hybrid compound consisted of polyoxoanion [PMo12V2O42]4-,[Co2(2,2-bpy)4(C2O4)]2+and [Co(2,2-bpy)3]2+. The most interesting feature is thatthe TMCs in compound2contains not only N-containing ligands but also oneO-containing ligand. Compound3represents a1-D zigzag chain-like structureconstructed from dimeric units of bi-capped polyoxoanions{[Cu(en)2]2[Cu(en)2(H2O)]2[SiMo8V6O42]2[Cu(en)2]}6-and transition metalcoordination fragment [Cu(en)2]2+. The adjacent chains are further interconnected intoa3-D supramolecular structure via hydrogen bonds. Compound4represents the first2-D layer structure constructed from bi-capped Keggin tungstovanadates andtransition metal complexes. Adjacent2-D tungstovanadates bridged TMCs layer withleft-and a right-handed helical1-D chains and crystal water molecules are furtherinterconnected into a3-D supramolecular structure via hydrogen bonds. Thesecompounds have been characterized by X-ray single crystal analyses, IR, EPR,elemental analysis, TG analyses and magnetism performance. The XRD and UV-vishave been performed on compounds1and2. The XPS of compounds1,2and4have been investigated. In addition, the results of magnetic measurements indicate the shortrange antiferromagnetic behavior of compounds3and4.2. tetra-capped Keggin molybdenum(tungsen)-(vanadium)-oxygen clustersThree tetra-capped Keggin molybdenum(tungsen)-(vanadium)-oxygen clusters(compounds5-7) were synthesized. Compounds5and6exhibit a1-D chain linked bybi-supported tetra-capped Keggin cluster and nickle coordination fragments. The1-Dchains are further assembled into a3-D supramolecular structure with differentpacking modes via hydrogen bonds. The unusual feature in compound5is thatcontain two organic ligands en and dien, and dien was obtained via deammoniationbetween ethylenediamine molecules under special conditions. Compound7representsa novel2-D layer structure constructed from tetra-capped bi-supporting Keggintungstovanadates and transition metal complexes. Adjacent layers are furtherinterconnected into a3-D supramolecular structure with a1-D channel via hydrogenbonds. The X-ray single crystal analyses, elemental analysis, IR, EPR, XPS and TGanalyses were performed on compounds5-7. The XRD, UV-vis and photocatalyticactivity have been performed on compound7. The magnetism performance ofcompounds5and7were investigated. In addition, the result of magneticmeasurements of compound5reveal the feature of antiferromagnetic exchange, andthe magnetic susceptibility of7demonstrated the presence of ferromagneticinteractions3. Molybdenum(tungsen)-oxygen clustersWe synthesized four tetra-capped Keggin tungsen(molybdenum)-oxygen clusters(compounds8-11). Compound8exhibit a novel1-D ladder-like chain structure,which is constructed from polyoxoanions, metal ions and organic ligands connectedtogether. The ladder-like chain structure is further interconnected into3-Dsupramolecular framework via hydrothermal bonding interactions. Compounds9-11are compounds based on POMs and discrete organic ligands. Through the hydrogenbonding interactions, compound9exhibits two infrequent (H2O)2water clusters andtwo kinds of different1-D double chains, further formed a novel3-D supramolecularnetwork. There are no direct interactions in10, but the polyoxoanions together with water molecules construct a scarcer3-D {[(SiW12O40)(H2O)2]4-}∞inorganicsupramolecular network through complex O···O and O···Ow1hydrogen bondinginteractions. Compound11exhibits a novel1-D chain structure, which constructedwith the [PMo12O40]3-anion linked with the adjacent one through O···O interactions.The1-D chain structure and the organic ligands formed a3-D supramolecularnetwork through the different hydrogen bond interactions. These compounds havebeen characterized by X-ray single crystal analyses, elemental analysis, IR, UV-vis,EPR, XPS and TG analyses. The photocatalytic activity and electrochemistryperformance of compounds8and10have been investigated.