Synthesis, Structures And Properties Of Lacunary Keggin Polyoxometalates Magnetic Complexes

Eleven new compounds based on polyoxometalates building blocks have beensynthesized by degradation and one pot self-assembly synthesis in conventional aqueoussolution. The structure of these compounds were characterized by single-crystal X-raydiffraction analyses, and at the same time test the related properties.1. Via aqueous solution synthesis strategy, K5[FeW12O40]·10H2O as precursor, three newmixed-metal sandwiched trivacant tungstoferrates1-3were obtained by degradation in theparticipation of ligand oxalate.Na2K2H8[FeIII2Mn2(H2O)2(FeIIIW9O34)2].22H2O (1)Na2K2H6[FeIII2MnIII2(H2O)2(FeIIIW9O34)2].28H2O (2)Na2K2H8[FeIII2Ni2(H2O)2(FeIIIW9O34)2].27H2O (3)Single-crystal and powder X-ray diffraction analyses revealed that the three compoundsare isostructural,1-3are composed of two [B-a-FeW9O34]11-sandwiched a mixed-metalcluster {Fe2M2O14(H2O)2}（M=Mn2+for1,Mn3+for2,Ni2+for3）.2. By way of aqueous solution synthesis methods, the reaction of GeO2、(NH4)6Mo7O24·4H2O and lanthanide in the participation of morpholine molecules produceseven new germanomolybdates4-10.(C4H10NO)8H5[Er(GeMo11O39)2].14H2O (4)(C4H10NO)8H5[Gd(GeMo11O39)2].13H2O (5)(C4H10NO)8H5[Dy(GeMo11O39)2].15H2O (6)(C4H10NO)8H5[Tb(GeMo11O39)2].14H2O (7)(C4H10NO)7H6[Pr(GeMo11O39)2].15H2O (8)(C4H10NO)8H5[Eu(GeMo11O39)2].25H2O (9)(C4H10NO)6H7[La(GeMo11O39)2].11H2O (10)Single-crystal and powder X-ray diffraction analyses revealed that the seven compoundsare isostructural,4-10are composed of two [GeMo11O39]8-sandwiched a LnIII(LnIII=Er, Gd,Dy,Tb, Pr, Eu and La).3. In NaAc aqueous solution, one3D network structure of compound11is synthesized.Na2K4(NH4)4[H2W12O42].14H2O (11)Compound11is composed of [H2W12O42]10–polyanion, Na+、K+、NH+counter ion anddissociative water molecules.[H2W12O42]10–polyanion is linked by Na+、K+ions forming3Dnetwork structure.