Synthesis, Structures And Properties Of Complexes Based On Arsenomolybdates And Lanthanide

Arsenatomolybdates, an important part in heteropolymolybdate chemistry, are ofconsiderable interest for their photoactive and magnetic properities. Herein, seven novelarsenatomolybdates have been synthesized from a conventional synthesis method by theone-pot reaction. The UV-Vis spectra, FT-IR spectra, thermal stability, fluorescence, andmagnetic property measurements were also made to well characterize this novellanthanide–arsenomolybdate complex.1. Begin with NaAsO2,（NH4）6Mo7O24·4H₂O and rare-metal in aqueous solution twonovel arsenatomolybdates were obtained:H₄[C₃H₅N₂]₁₁[(As₄^ШMo₈O₃₃)₃Pr（H₂O）₆]50H₂O （1）H₄[C₃H₅N₂]₁₁[(As₄^ШMo₈O₃₃)₃Nd（H₂O）₆]50H₂O （2）In Compound1, the Pr³⁺ion coordinated with three terminal oxygen atoms fromthree [AsШ4Mo8O33]6–fragment is in a nine-coordinate environment with the other sixsites occupied by six water molecules. Compound2is composed of an isolated Nd³⁺ionand three lacunary [AsШ4Mo8O33]6–units. It is known that the [AsШ4Mo8O33]6–units incompound1and2is first reported. In addition, compound1and2presents magneticproperties, providing useful information for exploring molecular magnetic materials withlanthanides.2. The reaction of NaAsO2,（NH4）6Mo7O24·4H₂O and lanthanide in aqueous solutionproduce two new arsenatomolybdates:（C₃H₅N₂）₄[Er（H₂O）₆(As^ШMo₁₀O₃₅)]2H₂O （3）（C₃H₅N₂）₄[Dy（H₂O）₆(As^ШMo₁₀O₃₅)]15H₂O （4）（C₃H₅N₂）₄[Tb（H₂O）₆(As^ШMo₁₀O₃₅)]2H₂O （5）In Compound3, the Er³⁺ion, in a eight-coordinate environment, is coordinated withtwo terminal oxygen atoms from three [As^ШMo₁₀O₃₅]7–fragment with the other six sitesoccupied by six water molecules. The structure of compound4and5is similar to compound3.The surface photovoltage spectroscopy （SPS） measurements show that the compound7is thep-type-like conduction characteristic.3. Two new arsenatomolybdates have been synthesized in aqueous solution, and theorganic ligand imidazole and mopholine were introduced to the reaction system.Na(C₄H₁₀NO)₅[(As^ШAs^VMo₉O₃₄)（H₂O）3（C₄H₉NO）] H₂O （6）[（CH₃）₄N]₄[C₃H₅N₂]H[As₂^ШMo₁₂O₄₂]9H₂O （7） The structural feature of compound6is the formation of1D chain in which[HAsШAsVMoVI9O33]3-clusters are covalently bonded to sodium coordination groups throughthe terminal oxygen of the {MoO6} tetrahedron. Compound6consist of imidazole,tetramethyl ammonium bromide and {As₂^ШMo₁₂O₄₂} unit.