Synthesis,Structures And Properties Of Complexes Based On Monovacant Dawson Tungstophosphates And Lanthanide

Based on trivacant Dawson type POMs as precursor, we successfully synthesized ninenew compounds in aqueous solution. These compounds were characterized via IR, TG, UVand X-ray powder diffraction. The photoluminescence and magnetic properties of thesecompounds were discussed.1.Seven new lanthanide polyoxometalates based on [α-P₂W₁₅O₅₆]^12-were successfullysynthesized:[（CH₃）₄N]₁₇Na₆（H₃O）₁₁[(α₂-P₂W₁₇O₆₁)₂Dy]₂·44H₂O （1）[（CH₃）₄N]20Na6（H3O）8[（α2-P2W17O61）2Tb]2·40H2O （2）[（CH₃）₄N]₁₇Na₆（H₃O）₁₁[(α₂-P₂W₁₇O₆₁)₂Eu]₂·40H₂O （3）[（CH₃）₄N]₁₆Na₆（H₃O）₁₂[(α₂-P₂W₁₇O₆₁)₂Er]₂·44H₂O （4）[（CH₃）₄N]₂₁Na₆（H₃O）₇[(α₂-P₂W₁₇O₆₁)₂Gd]₂·35H₂O （5）[（CH₃）₄N]₂₃Na₆（H₃O）₅[(α₂-P₂W₁₇O₆₁)₂Nd]₂·27H₂O （6）[（CH₃）₄N]₂₃Na6（H₃O）₅[(α₂-P₂W₁₇O₆₁)₂Pr]₂·36H₂O （7）The polyanions of the seven complexes are isomorphic. The LnIIIare sandwiched betweentwo lacunary Dawson-type [α₂-P₂W₁₇O₆₁]^10-anions and the two [(α₂-P₂W₁₇O₆₁)₂Dy]^17-moieties are linked by means of a centrosymmetric [Na₂（H₂O）₆（μ-H₂O）₂]²⁺unit. The emissionspectra of compounds1-3at room temperature exhibit the characteristic transitions of Dy³⁺、Tb³⁺and Eu³⁺ions. The magnetic measurements on compounds1,2and4reveal weakantiferromagnetic interactions between the lanthanide ions.2.A new sandwiched dimer [(α₂-P₂W₁₇O₆₁)₂Pr]^17-was isolated on the basis of trivacantpolyoxoanion [α-P₂W₁₅O₅₆]^12-and Pr³⁺:[NH（CH₂CH₂）₂O]₂₁Na₂（H₃O）₁₁[(α₂-P₂W₁₇O₆₁)₂Pr]₂·12H₂O （8）The adjacent two dimers are linked into1D chain by sodium ion and morpholine.3.A centrosymmertric dimer was synthesized by reaction of trivacant [α-P₂W₁₅O₅₆]^12-with Er³⁺:[（CH₃）₄N]₈[Er（H₂O）₈]₂[(α₂-P₂W₁₇O₆₁)Er（H₂O）₂]₂·12H₂O （9）Compound9is built from two [(α₂-P₂W₁₇O₆₁)Er（H₂O）₂]₇-fragments by means of twoEr–O–W link. Furthermore, the dimer is linked by [Er（H2O）8]³⁺to extend into a1D chain viahydrogen bonds interaction. The magnetic measurement on compound9reveals weakantiferromagnetic interactions between the lanthanide ions.