Design, Synthesis And Property Study Of Novel Vanadium-Based Metal-organic Materials

Materials science has developed such fascinating families of metal–organic materials?MOMs?,such as polygons,discrete polyhedral cage systems,and coordination polymers.The structural motifs in these materials include metal moieties?ions or clusters?coordinated by multidentate organic connectors.Based on the connectivity and geometry of building components,materials with different geometries and features?0D,1D,2D and 3D?can be assembled.Metal–organic polyhedra?MOPs?or cages?MOCs?constructed from the self–assembly of smaller molecular components are a significant class of compounds in supramolecular chemistry.They are usually coordinated by metal ions or metal clusters to form a zero–dimensional?0D?structures.Polyoxovanadates?POVs?,are an important branch of polyoxometalates and a unique class of metal clusters.Due to their structural diversity and coordination flexibility of POVs,they can be used as excellent candidates for inorganic building blocks for the construction of MOPs.Different from the structural features of MOPs,the periodic multidimensional ordered structure formed by the self–assembly of metal ions or metal clusters and organic ligand,we call coordination polymer.Currently,despite the wide variety of coordination polymers are constructed from various metals,vanadium–based coordination polymers are a few class,so constructing more vanadium–based coordination polymer materials and exploring their potential applications are also a very meaningful work.In summary,according to vanadium–based MOMs with different structural characteristics,they can be applied in the fields of gas storage and separation/purification,sensing,catalysis,magnetism,energy storage,drug transportation and so on.In this thesis,eight vanadium–based metal–organic materials were designed and synthesized by selecting different vanadium sources and tridentate carboxylate ligands,six of which were MOPs and the other two were vanadium–based coordination polymers.These novel vanadium–based metal–organic materials with specific geometries are obtained by adjusting different solvent ratios and temperatures,from which it is known that reaction conditions play a crucial role in the synthesis of these materials.In addition,according to the different physical and chemical properties of these compounds,they were separately subjected to ion exchange,magnetic and catalytic tests.1.Design and synthesis of metal–organic polyhedra?MOPs?with targeted geometries from predetermined secondary building units?SBUs?is a long–standing challenge in chemistry and material science.The theoretical prediction with reticular chemistry shows that there are 6 possible polyhedra from?3,4?–coordinated octahedron to?3,5?–coordinated icosahedron with minimal transitivity?simplest possible?.Except missing one polyhedron?mtr?due to the unfavorable angles,we report five MOPs based on these structures,including an octahedral?3,4?–coordinated 1?rdo?,an icosahedral?3,5?–coordinated 5?trc?,and three intermediate derived trinodal?3,4,5?–coordinated 2⁴?ghm,hmg,xum?.Remarkably,all these MOPs obey the minimal transitivitity principle and are well consistent with geometrical predictions.In addition,4 possesses good stability,so it can be used for the ion exchange reaction.The exchange of dimethylamine ions in 4 with cesium ions is successfully achieved,and finally X–rays single crystal diffraction was performed by crystals Cs–4 with good crystallinity after exchange.?H₂NMe₂?₁₂[?V₅O₉Cl?₆?L¹?₈]?1??H₂NMe₂?₁₆{[V₅O₉?OCH₃?]₄[MoV₅O₁₁?SO₄?]₄?L¹?₁₂}.?SO₄?₂?2??H₂NMe₂?₂₄{?V₅O₉Cl?₃[MoV₅O₁₁?SO₄?]₆?L¹?₁₄}.?SO₄?₆?3??H₂NMe₂?₂₀{[V₅O₈?CN?₂]₂[V₆O₁₁?SO₄?]₈?L¹?₁₆}.?SO₄?₄?4??H₂NMe₂?₁₆{[V₆O₁₁?SO₄?]₁₂?L¹?₂₀}.?SO₄?₂?5?{[Cs₂V₄O₈?CN?₂]₂[Cs₃V₅O₁₀?SO₄?]₈?L¹?₁₆}?Cs–4?L¹=benzene–1,3,5–tricarboxylic acid2.Under solvothermal conditions,we obtained a novel MOP?6?based on the?3,5?–coordinated small rhombicidodecahedron configuration.In this work,the structural characteristics of 6 were analyzed,and the magnetic properties of 6 were studied,which finally revealed that it has ferromagnetic interaction.In addition,a hollow pentagonal{V5S}cluster was first discovered in the MOP,which can be used as a 5–coordinated polyoxovanadate–based SBU during the construction of the framework structure.The discovery of the{V5S}cluster not only increases a new member to the limited family of polyoxovanadates,but also acts as a five–coordinated inorganic building block to self–assemble with more organic ligands to form more novel MOPs.?H₂NMe₂?₈₄{[V₆O₁₁?SO₄?]₁₂?L¹?₂₀}·?solvent??6?L¹=benzene–1,3,5–tricarboxylic acid3.Based on the current limited vanadium–based coordination polymers,in order to expand the types of vanadium–based coordination polymers,we successfully synthesized two two–dimensional novel mononuclear vanadium–based porous coordination polymers by one–step method under solvothermal conditions.VOSO4,Na3VO4 and two different sizes of tridentate ligands are chosen as starting reactants.Both of coordination polymers are characterized by single crystal X-ray diffractions,X-ray photoelectron spectroscopies,powder X-ray diffractions and other physicochemical methods.The structures of two vanadium-based coordination polymers are similar,and both are two-dimensional?2D?infinite rhombic lattice structures.Their structures are constructed by{V^IVO_X}?X=5 or 6?as their respective nodes and tridentate carboxylate ligands act as edges.Further,the adjacent 2D layers are joined by weak interaction to form three-dimensional?3D?supramolecular frameworks.In addition,two compounds have excellent catalytic properties for isopropanol and 2-butanol.[H₂N?CH₃?₂]₂[V^IVO?HL¹?₂]·?solvent??7?[H₂N?CH₃?₂]₂[V^IVO?HL²?₂]·?solvent??8?L¹=benzene–1,3,5–tricarboxylic acidL²=2,4,6-tris?4-carboxyphenyl?-1,3,5-triazine...