The Study Of The Decorated And Extended Structural Compounds Based On Polyoxometalates Building Units

The aim of this thesis is the synthesis of new polyoxometalate compounds on the basis ofKeggin, Standberg, Wells-Dawson and Preyssler type polyoxoanion clusters, which aredecorated or bridged by various transition metal compounds or rare earth compounds. Thestudy on synthetic conditions and rules for these new compounds and the exploration ofrelationships between structures and properties for these new compounds are also carried out.Nineteen new polyoxometalate compounds have been synthesized on the basis ofhydrothermal technique and/or water solution synthesis methods and structurallycharacterized by elemental analyses, IR, EPR, XRPD, TG and single crystal X-raydiffractions. The thermal stabilities, magnetic properties and fluorescent activity of thesecompounds have been studied.1. Five new polyoxometalate compounds on the basis of Keggin type polyoxoanioncluster have been hydrothermally synthesized and structurally characterized:[{PMo8V6O42}{Co(H2O)(2,2'-bpy)2}2][Co(2,2'-bpy)3]{PMo8V6O42}·6H2O (1)[{PMo8V6O42}{Cu(2,2'-bpy)}{Cu(2,2'-bpy)2}2]·3.5H2O (2)[4,4'-H2bpy]2[4,4'-Hbpy][PCuMo11O39]·H2O (3)[4,4'-H2bpy]2[4,4'-Hbpy][PZnMo11O39]·2.75H2O (4)[4,4'-H2bpy][Cu(4,4'-bpy)]2[HPCuMo11O39] (5)Compounds 1 and 2 exhibit transition-metal compound supporting polyoxometalatecluster structure. Compounds 3 and 4 show novel one-dimensional zigzag chains formed bytransition metal substituted Keggin heteropolymolybdate. Compound 5 possesses a noveltwo-dimensional network constructed from the interconnecting of polyoxomolybdate chains{HPCuMo11O39}n4n-and transition metal coordination polymer chains {Cu(4,4'-bpy)}nn+. Inaddition, [Cu4(2,2'-bpy)4(H2O)2(PO4)2](H3O)[PMo12O40] (6), a hybrid material based on[Cu4(2,2'-bpy)4(H2O)2(PO4)2]2+ and an α-Keggin polyoxoanion, has been prepared.2. Four new polyoxometalate compounds have been hydrothermally synthesized byvirtue of Standberg type polyoxoanion building units:(4,4'-H2bpy)0.5{[Ni(H2O)5][Ni(4,4'-Hbpy)(H2O)4][Mo5P2O23]} (7)(4,4'-H2bpy)0.5{[Co(H2O)5][Co(4,4'-Hbpy)(H2O)4][Mo5P2O23]} (8)[{Cu(im)4}2{H2Mo5P2O23}]·3H2O·(im) (9)[4,4'-H2bpy]2[{Cu(4,4'-bpy)2}Mo5P2O23]·4H2O (10)Compounds 7 and 8 exhibit novel bisupporting polyoxometalate cluster structure, wheretwo distinct transition metal complex fragments [M(H2O)5]2+ (M = Ni, Co) and[M(4,4'-Hbpy)(H2O)4]3+ (M = Ni, Co) are supported on the [Mo5P2O23]6-cluster. Compound9 also possesses bisupporting polyoxometalate cluster structure, where two {Cu(im)4}2+fragments are supported on the [H2Mo5P2O23]4-cluster. In compound 9, adjacent bisupportingdiphosphopentamolybdate clusters link to each other via the weak Cu…O interactiongenerating a uniform two-dimensional grid network. Compound 10 exhibits athree-dimensional framework with one-dimensional channels built from {Cu(4,4'-bpy)2}n2n+coordination polymer sheets pillared by [Mo5P2O23]6-clusters. The magnetic property forcompound 10 was studied and antiferromagnetic interactions exist in compound 10.3. Five new polyoxometalate compounds have been synthesized on the basis of lacunaryWells-Dawson anions decorated or connected by Ln3+ ions:KNa3[Nd2(H2O)10(α2-P2W17O61)]·11H2O (11)(H3O)[Nd3(H2O)17(α2-P2W17O61)]·6.75H2O (12)(4,4'-H2bpy)2[Nd2(H2O)9(α2-P2W17O61)]·4.5H2O (13)(4,4'-H2bpy)2[La2(H2O)9(α2-P2W17O61)]·4.5H2O (14)(4,4'-H2bpy)2[Eu2(H2O)9(α2-P2W17O61)]·5H2O (15)Compound 11 shows a bisupporting polyoxometalate cluster structure where two{Nd(H2O)7}3+ fragments are supported on the polyoxometalate dimer[{Nd(H2O)3(α2-P2W17O61)}2]14-, which represents the first bisupporting polyoxometalatecompound based on a polyoxometalate dimer. Compound 12 displays a one-dimensionalchain structure built up of bisupporting polyoxoanions [{Nd(H2O)7}2{Nd(H2O)3-(α2-P2W17O61)}2]8-and Nd3+ ions. Compounds 13-15 are isostructural, which show atwo-dimensional structure constructed of one-dimensional polyoxometalate chains[Ln(H2O)2(α2-P2W17O61)]n7n-linked by Ln3+ ions. Compounds 12-15 represent the firstcharacterized extended structure compounds formed by lacunary Wells-Dawson anions andtrivalent lanthanide ions. The fluorescent spectrum of compound 15 was measured, whichexhibits the characteristic transition of the Eu3+ ion.4. Four new polyoxometalate compounds on the basis of Preyssler type polyoxoanioncluster have been synthesized and structurally characterized:Na2[{Ce(H2O)8}4{Na(H2O)P5W30O110}]·12H2O (16)H4Na4[Nd2(H2O)14{Na(H2O)P5W30O110}]·22H2O (17)K2Na[Eu3(H2O)14(HNA)3{Eu(H2O)P5W30O110}]·3H2O (18)H2[Ce4(H2O)16(HNA)6{Na(H2O)P5W30O110}]·12H2O (19)Compound 16 exhibits a tetrasupporting polyoxometalate cluster structure where four{Ce(H2O)8}3+ fragments are supported on the [Na(H2O)P5W30O110]14-cluster. Compounds 17and 18 show a similar one-dimensional chain structure built from [Mn+(H2O)P5W30O110](14-n)-(Mn+=Na+ in 17, Eu3+ in 18) clusters linked by Ln3+ cations. Compound 19 has atwo-dimensional network constructed by one-dimensional [Ce2(H2O)10{Na(H2O)-P5W30O110}]n8n-chains and {Ce2(H2O)6(HNA)6}6+ linkers. Compounds 16-19 represent thefirst characterized modify or extended structure compounds based on Preyssler anions. Thefluorescent spectrum of compound 18 was measured, which exhibits the characteristictransition of the Eu3+ ion.