Study On Vanadate And Octamolybdate-based Compounds: Syntheses, Structures, And Properties

In this paper, by using two kinds of synthetic methods, nine novelcompounds have been obtained.1. Under aqueous synthesis condition, four novel compounds based onvanadate cluster inorganic-organic framework have been synthesized andcharacterized:[Zn3(bte)2(H2O)14][V10O28]·6H2O (1)[Zn2(btp)4(H2O)6][H2V10O28]·4H2O (2)[Zn3(btb)2(H2O)6][V10O28(H2O)6]·4H2O (3)[Zn2(bth)(H2O)10][H2V10O28]·6H2O (4)2. Under hydrothermal synthesis condition, five novel compounds based onoctamolybdate clusters have been synthesized and characterized:[Cu(bimb)(H2O)]2[β-Mo8O26](5)[Cu(bimb)]2[β-Mo8O26](6)[Cu3(btpe)4(COOH)2][β-Mo8O26](7)H[Ag3(H2O)2(btpe)2][β-Mo8O26](8)[Co2(btpe)4][β-Mo8O26](9)Compounds1-9were characterized by elemental analyses, IR, PXRD andsingle crystal X-ray diffractions. The structure feature of compound1is a2D(two dimension) to3D (three dimension) rotaxane structure. The structure ofcompound2shows1D (one dimension) chain with a pinwheel motif. Compound3have a similar ladder one-dimensional chain with an independent zincsix-nuclear cluster, which is very rarely. Compound4contains a polyoxometalateand organic metal chain. Compound5is a novel helix structure possessing twotypes of double helixes, namely both interconnected and interweaved doublehelixes, which represents the first example of the double helix based on POMs. Compound6contains both left helical layer and right helical layer structure.Compound7,8and9also possess a double helix in a3D structure. Aftercarefully analyzing theses structures, we found that the Keggin polyanions with aTdsymmetry showing a high symmetrical globular surface may be unfavorable toformation of helical structures. Choosing some low symmetrical POMs such asisopolymolybdates may be good at forming helix structures.Further, the photocatalytic properties of some compounds have beenstudied. The photocatalytic properties of5towards photodecomposition ofmethylene blue were investigated in details. Experimental results show that theobtained compound has excellent photocatalytic properties forphoto-decomposition of methylene blue, and also shows that the compound5is ahighly efficient and stable photocatalyst.