Reactions of carbon dioxide with lanthanide ethylenediaminetetraacetates M[Ln(EDTA)(H₂O)₃]·5H₂O (M = NH₄, Na or K; Ln = La or Ce) result in the formation of highly water-soluble lanthanide carbonates with ethylenediaminetetraacetates (NH₄)₅[La₃(CO₃)(EDTA)₃(H₂O)₃]·12H₂O (1), Na₈[Ln₂(CO₃)₃(EDTA)₂]·17.5H₂O (Ln = La, 2; Ce, 3), and K₅[Ln₃(CO₃)(EDTA)₃(H₂O)₃]·13.5H₂O (Ln = La, 4; Ce, 5; H₄EDTA = ethylenediaminetetraacetic acid) in dimethylformamide–water solution, which have been fully characterized. The main structures of these five complexes are all based on the [Ln(EDTA)]⁻ unit, where carbonates participate due to coordination in μ₁:η²(O,O) and μ₂:η²(O,O′):η²(O,O′) fashion. The reactions of lanthanum ethylenediaminetetraacetate with CO₂ have been monitored via¹³C NMR measurements. Furthermore, the calcined products of 1 and 2 are used for the oxidative coupling reaction of methane (OCM). The results demonstrate the good catalytic performances of La₂O₃ or La₂O₂CO₃ from 1 and a mixture of La₂O₂CO₃ and Na₂CO₃ from 2. The coordination modes of the lanthanide carbonates in precursors 1 and 2 may provide a model for the interaction of lanthanide carbonates, which is useful for the OCM reaction.

中文翻译：

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高水溶性二聚和三聚镧系元素碳酸盐与乙二胺四乙酸盐作为甲烷氧化偶联反应催化剂的前体

二氧化碳与镧系元素乙二胺四乙酸盐 M[Ln(EDTA)(H ₂ O) ₃ ]·5H ₂ O（M = NH ₄、Na 或 K；Ln = La 或 Ce）反应生成高度水溶性的镧系元素碳酸盐与乙二胺四乙酸盐 (NH ₄ ) ₅ [La ₃ (CO ₃ )(EDTA) ₃ (H ₂ O) ₃ ]·12H ₂ O ( 1 ), Na ₈ [Ln ₂ (CO ₃ ) ₃ (EDTA) ₂ ]· 17.5H ₂ O (Ln = La, 2 ; Ce,3 ), 和 K ₅ [Ln ₃ (CO ₃ )(EDTA) ₃ (H ₂ O) ₃ ]·13.5H ₂ O (Ln = La, 4 ; Ce, 5 ; H ₄ EDTA = 乙二胺四乙酸)在二甲基甲酰胺中–水溶液，已充分表征。这五种配合物的主要结构均基于[Ln(EDTA)] ^-单元，其中碳酸盐由于在μ ₁ :η ² (O,O) 和μ ₂ :η ² (O,O')中的配位而参与其中:η ²(O,O') 时尚。已通过¹³ C NMR 测量监测乙二胺四乙酸镧与 CO _{2的反应。}此外，1和2的煅烧产物用于甲烷的氧化偶联反应（OCM）。结果表明来自1的La 2 _O 3_或La ₂ O ₂ CO ₃以及来自2的La ₂ O ₂ CO ₃和Na ₂ CO ₃的混合物具有良好的催化性能。. 前驱体1和2中镧系元素碳酸盐的配位模式可以为镧系元素碳酸盐的相互作用提供模型，这对 OCM 反应很有用。