Highly water-soluble dimeric lanthanum and cerium ethylenediaminetetraacetes with carbonate K₈[Ln₂(CO₃)(Hcit)(EDTA)₂]Cl·10.5H₂O [Ln = La, 1; Ce, 2] and K₆[Ln₂(CO₃)(Hmal)(EDTA)₂]·12.5H₂O [Ln = La, 3; Ce, 4] (H₄cit = citric acid, H₃mal = malic acid, and H₄EDTA = ethylenediaminetetracetic acid) have been isolated from the reactions of lanthanide ethylenediaminetetraacetate with citric or malic acid and carbon dioxide in alkaline solution. The complexes have been well characterized by elemental analysis, IR, TG-DTG, ¹³C{¹H} in solution and ¹³C-NMR spectra in solid state. X-ray structural analyses show that carbonates in 1 ∼ 4 are connected by two lanthanide EDTAs respectively, while the others are occupied by citrate or malate. ¹³C NMR spectra show obvious downfield shifts, indicating coordination of mixed-ligand lanthanides. The carbonates in 1 ∼ 4 are activated with bond distances 1.252(8) – 1.310(9) Å that are comparable to those [1.217(3) and 1.361(3) Å] in formic acid. The successful isolations of these complexes provide valuable species for mixed Pechini method in the constructions of lanthanide mixed-oxides.

高水溶性二聚镧和铈乙二胺四乙酸酯与碳酸盐 K ₈ [Ln ₂ (CO ₃ )(Hcit)(EDTA) ₂ ]Cl·10.5H ₂ O [Ln = La, 1 ; Ce, 2 ]和K ₆ [Ln ₂ (CO ₃ )(Hmal)(EDTA) ₂ ]·12.5H ₂ O [Ln = La, 3 ; Ce, 4 ] (H ₄ cit = 柠檬酸，H ₃ mal = 苹果酸，H ₄EDTA = 乙二胺四乙酸）已从镧系元素乙二胺四乙酸盐与柠檬酸或苹果酸和二氧化碳在碱性溶液中的反应中分离出来。配合物已通过元素分析、IR、TG-DTG、溶液中的¹³ C{ ¹ H} 和固态的¹³ C-NMR 光谱进行了很好的表征。X射线结构分析表明，1 ~ 4中的碳酸盐分别由两个镧系EDTA连接，其余被柠檬酸盐或苹果酸盐占据。¹³ C NMR 光谱显示出明显的低场位移，表明混合配体镧系元素的配位。1 ∼ 4 中的碳酸盐被激活的键距离为 1.252(8) – 1.310(9) Å，与甲酸中的 [1.217(3) 和 1.361(3) Å] 相当。这些配合物的成功分离为混合Pechini方法在镧系元素混合氧化物的构建中提供了有价值的物种。