Four hetero-polyoxometalate compounds were obtained in aqueous solutions, following the synthetic combination of Na₉[B-α-As^IIIW₉O₃₃] with the 4f tetravalent cerium cation in the presence of the formate ligand at different pH values (ranging from 1.5 to 6). All four molecules [{Ce₆(μ³-O)₄(μ³-OH)₄(HCOO)_3,5}₄(As^IIIW₉O₃₃)₄]²⁻ compound 1, [(Ce₆(μ³-O)₄(μ³-OH)₄)(H₂O)₄(As^IIIW₉O₃₃)(HCOO)₉]⁶⁻ compound 2, [(Ce₆(μ⁴-O)₃(μ³-O)₅ (μ²-H₂O)₃)(HCOO)₃(As^VW₉O₃₄)₃]²²⁻ compound 3, and [(W₄O₁₀){(Ce₆(μ³-O)₅(μ⁴-O)₃(μ²-H₂O))(As^VW₉O₃₄)₃}₂]⁴⁴⁻ compound 4 were constructed around one to four hexanuclear cerium clusters of [Ce₆O₈] type. For the compounds 1–3, the arsenato-polytungstate POM units and formate ligands were associated and participated in the stabilization of one cerium(IV)-bearing hexanuclear unit in a cyclic motif (1), a monomeric POM species for 2, and a trimeric POM species for 3. However, in the last molecular system (4), only inorganic entities were bonded to the hexameric cerium(IV) clusters. From the structural point of view, compound 4 appeared as the association of two compound 3 entities, in which the formate ligands were replaced by an inorganic tungsten-based sub-unit coming from the partial decomposition of the {As^IIIW₉O₃₃} precursor. The behavior and the association modes of the four molecular species were explained on the basis of the pH variation used in their syntheses. All four compounds were characterized by single-crystal X-ray diffraction, IR spectroscopy, TGA, SEM/EDX microscopy, and ICP analyses. The solution behavior was assessed on compound 3 by using small angle X-ray scattering (SAXS) measurements.

中文翻译：

---

pH对铈影响^IV - [作为^III W¯¯ ₉ ö ₃₃ ] ^9-协会六核铈的形成（IV）氧代羟簇由trivacant聚阴离子稳定†

Na ₉ [B-α- ^AsIII W ₉ O ₃₃ ]与4f四价铈阳离子在甲酸配体存在下，在不同pH值下合成后，在水溶液中获得了四种杂多金属氧酸盐化合物。 1.5至6）。所有四个分子[{铈₆（μ ³ -O）₄（μ ³ -OH）₄（HCOO）_3,5 } ₄（如^III w ^ ₉ ö ₃₃）₄ ] ^2-化合物1，[（铈₆（μ ³ -O）₄（μ ³ -OH） ₄）（H ₂ O） ₄（如^III w ^ ₉ ø ₃₃）（HCOO） ₉ ] ^-6-化合物2，[（铈₆（μ ⁴ -O） ₃（μ ³ -O） ₅（μ ² -H ₂ O） ₃）（HCOO） ₃（如^V w ^ ₉ ø ₃₄） ₃ ] ^22-化合物3和[（W ₄ ø ₁₀）{（铈₆（μ ³ -O） ₅（μ ⁴ -O） ₃（μ ² -H ₂ O））（如^V w ^ ₉ ø ₃₄） ₃ } ₂ ] ^44-化合物4构建围绕一至四个六核铈簇的[Ce ₆ O ₈ ]类型。对于化合物1-3，砷化多聚钨酸盐POM单元和甲酸盐配体相关联并参与了一个环状基序（ 1）中带有铈（ IV）的六核单元的稳定化，这是一种POM单体2个，三聚体POM种类为3个。但是，在最后一个分子系统（4）中，只有无机实体键合到六聚铈（IV）簇上。从结构的角度来看，化合物4表现为两个化合物3实体的缔合，其中甲酸配体被{As ^III W ₉ O ₃₃的部分分解而来的无机钨基亚单元所取代。}前体。在合成中使用的pH值变化的基础上，解释了这四种分子的行为和缔合模式。所有四种化合物均通过单晶X射线衍射，IR光谱，TGA，SEM / EDX显微镜和ICP分析进行了表征。通过使用小角X射线散射（SAXS）测量，对化合物3的溶液行为进行了评估。