Synthesis, Structure And Characterization Of Polyoxovanadate Decorated By Metal-Ligand

This thesis reported a series of new polyoxometalates (POMs) on the basis of NH₄VO₃, NaAsO₂ by exploiting appropriate metal cations or organic ligands. The study on the synthetic conditions and rules for these new compounds and the exploration of relationships between structures and properties for these new compounds were also carried out. Nine new polyoxovanadates have been synthesized by using hydrothermal technique, and structurally characterized by single crystal X-ray diffractions, elemental analyses, IR, TG, XRD, UV, cyclic voltammetry, and so on.1. Two polyoxovanadate compounds have been synthesized with the transition metal and organic ligand 5,5'-Dimethyl-2,2'-Bipyridine: [Cd(5,5'-mbpy)₂]₃[V₆O₁₈]·4H₂O (1) [Fe(5,5'-mbpy)₃]₂[V₁₀O₂₈]·6H₂O (2) Compound 1 consists of a 1-D chiral helical structure via covalent bond interactions. Compand 2 is a 3-D supramolecular network with 1-D channel via hydrogen interactions.2. Three supramolecular compounds have been hydrothemally synthesized on the basis of [As₈V₁₄O₄₂]4- and [M(4,4'-mbpy)₃]₂+ via intermolecular hydrogen and aryl packing interactions: [Cd3VO3(4,4'-mbpy)6(H₂O)4 ][Cd(4,4'-mbpy)₃]₄[As₈V₁₄O₄₂ (H₂O)]3 (3) [Mn3VO3(4,4'-mbpy)6(H₂O)4][Mn(4,4'-mbpy)3]4[As₈V₁₄O₄₂ (H₂O)]3 (4) Ni2(4,4'-mbpy)6[As₈V₁₄O₄₂SO4] (5)The structures of compounds 3 and 4 are similar each other with the different types of metals. Interestingly, there is {β-[As₈V₁₄O₄₂]4?} cluster in compound 5, different from the {α-[As₈V₁₄O₄₂]4?} in compounds 3 and 4.3. Four supramolecular 1-D supramolecular compounds have been hydrothemally synthesized on the basis of [As₈V₁₄O₄₂]4- via different transition metals and 5,5'-mbpy ligand: [Ni₂(5,5'-mbpy)5][As₈V₁₄O₄₂(H₂O)] (6) Zn₂(5,5'-mbpy)5[As₈V₁₄O₄₂(H₂O)]·1.75H₂O (7) Cd₂(5,5'-mbpy)5[As₈V₁₄O₄₂(H₂O)]·2H₂O (8), [Cu₄(5,5'-mbpy)6[As₈V₁₄O₄₂(H₂O)] (9)Compounds 6, 7 and 8 consist of a 1-D chiral helical structure via covalent bonds. And the [As₈V₁₄O₄₂]4- anions are connected with each other by [M(5,5'-mbpy)2]2+ in compounds 6, 7 and 8. The [As₈V₁₄O₄₂]4- anions are connected each other by [M2(5,5'-mbpy)3]2+ in compound 9.