Constructing Novel Polyoxotungstate Based On Polyoxometalate Building Blocks

The aim of this thesis is the synthesis of new framework compounds on the basis ofpolyoxovanadates.The study on synthetic conditions and rules for these new compounds,topological analyses,and the exploration of relationships between structures and propertiesfor these new compounds are also carried out.Twelve new compounds have been synthesizedon the basis of hydrothermal technique and/or mixed solventthermal synthesis methods andstructurally characterized by elemental analyses,IR,XRPD,TG and single crystal X-raydiffractions.The thermal stabilities,magnetic properties and electrochemical activities ofthese compounds have been studied.1.Two new compounds have been hydrothermally synthesized by virtue of transition metalions and phosphorus-tungstate oxides with the same configurations:K[Cu(phen)₂(H₂O)]₂[PW₁₂O₄₀]·2H₂O (1)K[Mn(phen)₂(H₂O)]₂[PW₁₂O₄₀]·2H₂O (2)Both compound 1 and 2 are based on Keggin type polyoxometalate {PW₁₂O₄₀} whichrepresent the first examples containing one-dimensional chain by alkaline metal-bridgedbisupporting polyoxoanion units.2.To construct novel polyoxoanion clusters,based on the lacunary polyoxometalate asprecursor and decoration with transition metal,rare earth atoms and organicfragments.Because of theirs diversiform coordination environments,higher oxidation statesand stronger coordination capacity of lanthanide ions,we were trying to import the rare earthions,transiton metal ions and small molecule to the polyoxoanoin building blocks,on thechance of largely impove the properties of such polyoxoanions.At the same time,this class ofpolyoxoanion which contains more than one transition metal ions such as Cu,Fe,Co,Ni,Znetc.,maybe exhibiting excellent magnetic property luminesce property and photovoltage.K₄LaH [As₂W₂₀CuO₆₇(H₂O)₃]Cl₂·22.5 H₂O (3)Na2 [Cu(en)]₅ [Ce₂(AsW₁₁O₃₉)₄]·19H₂O (4)K₂Na₂(NH₄)₁₈[(VO)(SO)(As₄W₄₀O₁₄₀)]·30H₂O (5)[Zn (phen)₂]₂[Zn₆(phen)₂(AsW₉O₃₃)₂] (6)K₁₁H₂Zn [(AsW₉O₃₃)₂(ZnCl)₆] Cl·27H₂O (7)Compound 3 is an novel sandwich-type polyoxoanion construct of an La atom froming anovel 3d-4f structure.Compound 4 and 5 was sysnithized through hydrothermal technique.The two {AsW₁₁} units which connected through rare earth atoms and five [Cu(en)]fragments linked to the polyoxanions framework respectively to construct a 2-D extendedstructures.In compound 6,we were successful imported the {VOs} and a {SO₃} units to the {As₄W₄₀} fragment.Compound 7 and 8 were two new sandwich-type polyoxoanions whichcontain two novel six-nucleus clusters and have never been reported.This was firstly toimport highly Zn clusters to the polytungstoarsenate.3.To construct highly-nucleus polytungstoarsenate clusters based on [As₂W₁₉O₆₇(H₂O)]^14-unit by using the strategy of self-assembly in solution.As we know,most nanosized POMclusters were prepared via the"bottom-up"control of aggregation process to get the finalhuge aggregates In synthesition of huge polytungstoarsenate,the building blocks such as{AsW₉}and {As₂W₁₉} paid more attentions because the As^â…¢have a alone pair of electronswhich lead this class of building blocks difficult to form saturated structure.This will make achance to form novel connect fashion and new structues.K₈Na₄ [(H₂O)As₄W₁₉O₇₀]·21.5H₂O (8)K₃Na₂₂[{W₄O₉(H₂O)₂} {As₂W₁₉O₆₇(H₂O)}₂].14H₂O (9)K₁₀Na₁₀[(W₁₃O₃₃)(H₂O)₆(OH)₄(AsW₉O₃₃)₄O₂₉]·50H₂O (10)Compound 9 and 10were all obtained based on the {As2W19} as the precursor andself-assembly in the solution.In compound 9,we firstly import the {As₂O} fragment to the[As₂W₁₉O₆₇(H₂O)]^14- and got a novel sandwich-type compound.Compound 10 is the novelhigh-nucleus polytungstoarsenates and this kinds of pure polytungstoarsenates had rare bereported till now.