Complex formation of anserine with uranyl in aqueous solution: Thermodynamic studies and structural analysis

Chen, Wen; Liu, Bijun; Mu, Wanjun; Yu, Qianhong; Yin, Tian; Tu, Jun Bo; Li, Xingliang; Yang, Yong; Luo, Shi-Zhong

doi:10.1016/j.microc.2018.07.018

Cited by 3 publications

(1 citation statement)

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“…Potentiometric experiments were carried out using a specially designed vessel as previously described. , The electromotive force (in millivolts) was measured by a pH meter (model 713, Metrohm) equipped with a combined pH electrode (6.0259.100 Unitrode, Metrohm). The original 3.0 mol·L –1 KCl salt bridge solution of the electrode was substituted with a 1.0 mol·L –1 sodium chloride solution to prevent the formation of insoluble KClO 4 in the electrode joint sleeve that is in contact with the working solution (1.0 mol·L –1 NaClO 4 ).…”

Section: Methodsmentioning

confidence: 99%

Complexation of Light Trivalent Lanthanides with N-(2-Hydroxyethyl)ethylenediamine-N,N′,N′-triacetic Acid in Aqueous Solutions: Thermodynamic Analysis and Coordination Modes

Zhang

Liu

et al. 2019

Inorg. Chem.

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N-(2-Hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid (HEDTA, denoted as H 3 L) is a strong chelating ligand that is widely used in the separation of f elements as relevant to the nuclear fuel cycle. There is much to be known about the structure and composition of the coordination sphere of the complexes of HEDTA with lanthanides. The complexation of HEDTA with light lanthanides (La 3+ , Nd 3+ , and Eu 3+ ) was investigated thermodynamically and structurally in aqueous solutions. Potentiometry and microcalorimetry were performed to acquire the complexation constants (25−70 °C) and enthalpies (25 °C), respectively, at I = 1.0 mol•L −1 NaClO 4 . Coordination modes of the complexes were analyzed by luminescence spectroscopy and NMR spectroscopy. The results indicate that there are two successive Ln 3+ /HEDTA complexes, LnL aq and Ln 2 (H −1 L) 2 2− (Ln 3+ refers to La 3+ , Nd 3+ , and Eu 3+ ; H −1 L 4− refers to deprotonation of the hydroxyl group) during titration. The hydroxyl group of HEDTA is coordinated in the Ln 3+ /HEDTA complex. The dinuclear Ln 2 (H −1 L) 2 2− complex is present as a carboxyl-bridged centrosymmetric dimer, and two carboxyl groups in bridging positions are coordinated to two adjacent Ln 3+ cations. Complexation of NdL aq is exothermic, while formation of the hydrolytic complex Nd 2 (H −1 L) 2 2− is endothermic. Both NdL aq and Nd 2 (H −1 L) 2 2− complexes are driven by entropic force. These data will help to predict the behavior of lanthanides in the separation process, where HEDTA is used as the aqueous complexant.

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Section: Methodsmentioning

confidence: 99%