| Thirty-one crystals of polyoxometalates (1D, 2D, 3D) were prepared by means of middle hydrothermal technique, molecular design and self-assembly, and characterized structurally by single crystal X-ray diffraction. The thermal stability, activity of catalysis and magnetism of some compounds were systematically studied. The continuous appearance of P-V-O, P-Mo-O, V-Mo-O, V-O system with novel structure enrich polyoxometalate chemistry, the reaction characterization and the synthesis law of Molybdates, Tungstates and Vanadates under hydrothermal conditions were explored. The factors that influence the synthesis and structure of the compounds, such as the selection, ratio, adding-order, concentration of material, the acidity, the reaction temperature and the reaction time were studied, which can accumulate helpful experience for the development of novel catalyst, conductive material and magnetic materials.Five polyoxometalate crystals of P-V-O system were synthesized and characterized structurally: (NH3CH2CH2NH3)4[CoV6O8(HPO4)6(PO4)2 (H2O)2].3H2O(1),(NH3CH2CH2NH3)4[CoV6O8(HPO4)6(PO4)2(H2O)2] .4H2O(2), (NH3CH2 NH3CH2 CH2NH3)4[FeV8O12(HPO4)6-(PO4)2(H2O)2].5H2O(3), (NH3CH2CH2NH3)4 [NiV8O12 (HPO4)6(PO4)2(H2O)2].5H2O(4), [(VO2)2 (HPO4)(2,2'-bipy)2].H2O(5). Compound (1), (2), (3), (4) have three-dimensional channel structure, which arebuilt up from infinite two-dimensional layer structure alternately linked by P-V-O, and MO4(H2O)2(M=Co, Cu, Fe, Ni) octahedral with four PO4 tetrahedra by sharing corners during the layers. Compound (5) is an inorganic-organic hybrid by 2,2'-bipy molecule directly bonded to anion clusters.Five polyoxometalate crystals of P-Mo-O systemwere synthesized and characterized structurally: (H2en)4[Mn3Mo12O30(HPO4)6(H2PO4)2].8H2O(6), (H2en)6[Mn2MO12O30(PO4)2(HPO4)4(H2PO4)2].5H2O(7), (H2en)g.[MnMo12O30 (PO4)2 (HPO4)6].H2O(8), (H3NCH2CH2 NH3)6[P4Mo10O46].10H2O(9), (H3NCH2CH2NH3)2 [(HPO4)2Mo2O15] (10). Compound (6), (7), (8) have the same building clock Mn[Mo6P4]2. Because of different coordination environment and linkage means of Mn element, the three compounds possess completely different space structures. In structure (6) Mn(1)2+ links with two [Mo6P4] units by sharing corners and then forms Mn(1)[Mo6P4]2, while Mn(2) links to four different Mn(l)[Mo6P4]2 clusters and forms plenary channel structure. Polyanion [P2Mo5O23] of compounds(9) and (10) consists of five MoOe octahedra which form a ring by sharing corners and edges, and two PO4 tetrahedra which exist in two sides of the ring plane by three oxygen atoms bonded to the Mo-O cluster.Seven polyoxometalate crystals of V-Mo-O system were synthesized and characterized structurally: (H2en)3H3O{Mo8V4O36(VO4)(VO)2} .4H2O(11), [H2en]4H[AsvMo8VIV4O40(VVO2)2].6H2O(12), [Hen][H2en]2 [AsIIIAsvMo8VIV4O40].5H2O(13), [Cu(en)2]4[SiMo8VV4O40(VIVO)2][MoO4]2.5H2O(14), [Ni(Phen)3]2[SiMo10VIV2O40(VIVO)2].2H2O(15),.2H2O(17). Compound (11) and (12) are chain structure, which are built up from the linkage of a-Keggin building clock with VO units on the capped site. (13) is formed by linking two AsO4 caps to Keggin cluster. Compound (14), (15), (16), (17) are taken shape by linking two VIVO caps to Keggin cluster.Four polyoxometalate crystals of As-V-O system were synthesized and characterized structurally : Anion cluster of compound [Ni(en)3]2[Ni(en)2(H2O)2] [As6V15O42].4H2O(18) consists of fifteen square cones of VOs and three group handlike units of As2O5. Anion clusters of (Hen)3(H3O+)[As8VIV14O42].2H2O(19) and(H3O+)8[As16VIV28O42(H2O)2].4H2O(20) are composed of fourteen VO5square cones and four handlike As2O5 units. Anion cluster of [N(CH2CH3)3]2 [SV12O40(As2O)4].2H2O(21) is [As88V4O40(SO4)]2-that is a crystallographic disordered structure, which has twelve VO6 octahedra and four group handlike As2O5 units.Three polyoxometalate crystals of P-W(V)-O system were synthesized and characterized structurally: compound {PW9V3O40[Ag(2, 2'-bip... |
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