当前位置:
X-MOL 学术
›
Inorg. Chem. Front.
›
论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Structural and thermodynamic aspects of water–carbonate exchange equilibrium for MIII/IV–EDTA–carbonate systems†
Inorganic Chemistry Frontiers ( IF 7 ) Pub Date : 2018-11-27 00:00:00 , DOI: 10.1039/c8qi01062e Rafał Janicki 1, 2, 3, 4 , Anna Mondry 1, 2, 3, 4
Inorganic Chemistry Frontiers ( IF 7 ) Pub Date : 2018-11-27 00:00:00 , DOI: 10.1039/c8qi01062e Rafał Janicki 1, 2, 3, 4 , Anna Mondry 1, 2, 3, 4
Affiliation
The results of a thermodynamic description of ternary M–EDTA–carbonate (where M = Er(III), Th(IV)) complex formation are presented. The crystal structures of the novel [C(NH2)3]3[Er(EDTA)(CO3)]·H2O (I) and [C(NH2)3]4[Th(EDTA)(CO3)2]·5H2O (II) compounds were determined. The structural and UV-vis-NIR spectroscopic results of crystal I served as the model data to analyze the stoichiometry and stability of the Er(III)–EDTA–carbonate system in aqueous solutions. The formation of the [Er(EDTA)(CO3)]3– complex in solution under different conditions was examined by complementary techniques including temperature dependent UV-vis-NIR and NMR spectroscopy as well as potentiometry. It was established that the affinity of the carbonate for the Er(III)–EDTA chelate is strongly pH dependent. Thus reaction (A) [Er(EDTA)(H2O)2]− + CO32– ⇄ [Er(EDTA)(CO3)]3– + 2H2O is more favoured at near neutral pH, while reaction (B) [Er(EDTA)(OH)(H2O)2]2– + CO32– ⇄ [Er(EDTA)(CO3)]3– + 2H2O + OH− occurs under more basic conditions. The log β values were found to be 3.66 ± 0.07 and 0.20 ± 0.12 for reactions (A) and (B), respectively. The temperature dependence of log β allowed the determination of the enthalpy and entropy changes of both reactions for the first time (ΔH(A) = −2.8 ± 0.8 kJ mol−1, ΔS(A) = 62 ± 3 J mol−1 K−1 and ΔH(B) = 28.1 ± 4.6 kJ mol−1, ΔS(B) = 92 ± 15 J mol−1 K−1). These data indicate that the carbonate anion more readily displaces H2O than the OH− ligand. The obtained results are important not only from the point of view of environmental lanthanide and actinide mobility, but also for designing MRI contrast agents.
中文翻译:
M III / IV –EDTA–碳酸盐系统中水-碳酸盐交换平衡的结构和热力学方面†
给出了M-EDTA-碳三元碳酸盐(其中M = Er(III),Th(IV))配合物形成的热力学描述结果。新型[C(NH 2)3 ] 3 [Er(EDTA)(CO 3)]·H 2 O(I)和[C(NH 2)3 ] 4 [Th(EDTA)(CO 3))2 ]·5H 2 O(II)的化合物被确定。晶体I的结构和UV-NIR光谱结果作为模型数据,用于分析Er(III)的化学计量和稳定性)–水溶液中的EDTA –碳酸盐系统。通过补充技术,包括依赖于温度的UV-vis-NIR和NMR光谱以及电位计,研究了在不同条件下溶液中[Er(EDTA)(CO 3)] 3–络合物的形成。已经确定,碳酸盐对Er(III)-EDTA螯合物的亲和力强烈依赖于pH值。因此,反应(A)[Er(EDTA)(H 2 O)2 ] - + CO 3 2- ⇄[Er(EDTA)(CO 3)] 3- + 2H 2 O在接近中性pH时更有利, (B)[Er(EDTA)(OH)(H 2 O)2 ]2- + CO 3 2- ⇄[二(EDTA)(CO 3)] 3- + 2H 2 O + OH -更基本的条件下发生。日志 β发现值分别为3.66±0.07和用于反应(A)和(B)0.20±0.12。日志的温度依赖性 β允许的两个反应的首次(焓和熵的变化的确定Δ ħ (A) = -2.8±0.8千焦耳摩尔-1,Δ小号(A) = 62±3Ĵ摩尔- 1 K -1和ΔH (B) = 28.1±4.6 kJ mol -1,ΔS (B)= 92±15J mol -1 K -1)。这些数据表明,碳酸根阴离子更容易位移ħ 2 ö比OH -配位体。所获得的结果不仅从环境镧系元素和act系元素迁移率的观点来看是重要的,而且对于设计MRI造影剂也很重要。
更新日期:2018-11-27
中文翻译:
M III / IV –EDTA–碳酸盐系统中水-碳酸盐交换平衡的结构和热力学方面†
给出了M-EDTA-碳三元碳酸盐(其中M = Er(III),Th(IV))配合物形成的热力学描述结果。新型[C(NH 2)3 ] 3 [Er(EDTA)(CO 3)]·H 2 O(I)和[C(NH 2)3 ] 4 [Th(EDTA)(CO 3))2 ]·5H 2 O(II)的化合物被确定。晶体I的结构和UV-NIR光谱结果作为模型数据,用于分析Er(III)的化学计量和稳定性)–水溶液中的EDTA –碳酸盐系统。通过补充技术,包括依赖于温度的UV-vis-NIR和NMR光谱以及电位计,研究了在不同条件下溶液中[Er(EDTA)(CO 3)] 3–络合物的形成。已经确定,碳酸盐对Er(III)-EDTA螯合物的亲和力强烈依赖于pH值。因此,反应(A)[Er(EDTA)(H 2 O)2 ] - + CO 3 2- ⇄[Er(EDTA)(CO 3)] 3- + 2H 2 O在接近中性pH时更有利, (B)[Er(EDTA)(OH)(H 2 O)2 ]2- + CO 3 2- ⇄[二(EDTA)(CO 3)] 3- + 2H 2 O + OH -更基本的条件下发生。日志 β发现值分别为3.66±0.07和用于反应(A)和(B)0.20±0.12。日志的温度依赖性 β允许的两个反应的首次(焓和熵的变化的确定Δ ħ (A) = -2.8±0.8千焦耳摩尔-1,Δ小号(A) = 62±3Ĵ摩尔- 1 K -1和ΔH (B) = 28.1±4.6 kJ mol -1,ΔS (B)= 92±15J mol -1 K -1)。这些数据表明,碳酸根阴离子更容易位移ħ 2 ö比OH -配位体。所获得的结果不仅从环境镧系元素和act系元素迁移率的观点来看是重要的,而且对于设计MRI造影剂也很重要。