A comparative study on the coordination of diglycolamide isomers with Nd(iii): extraction, third phase formation, structure, and computational studies

Abstract

The inhomogeneous interactions of M–Oamide in the LII ligand result in differences between the metal-ion extraction performances of two isomeric ligands.

Study on the extraction of lanthanides by isomeric diglycolamide extractants: an experimental and theoretical study

“…The symmetric stretching absorption peaks of the ether O bond shift from 1117 cm −1 of pure L II to 1121 cm −1 (La), 1122 cm −1 (Nd) and 1125 cm −1 (Eu), respectively. 36 It indicates that the L II molecule can form tridentate complexes with La( iii ), Nd( iii ), and Eu( iii ) through two carbonyl groups and one ether group. The studies by Kou et al illustrated the structure of the complex between L I and Eu( iii ), 16,37,38 and the results showed that Eu( iii ), in the center of the complex, is surrounded by three L I molecules with tridentate coordination, and the L II complex also has a similar structure.…”

“…† Both L I and L II are coordinated with lanthanide ions as a tridentate ligand, which is in agreement with the previous studies. 36,39 …”

“…Moreover, the difference of the electrostatic potential of O amide1 and O amide2 in L II is also larger than that in L I . 36 So there exists a larger difference in the ability of electron-donation of the two amide O atoms in L II than in L I . The calculation results of Mayer bond orders (MBOs) of M–O ether , M–O amide1 and M–O amide2 (M = La, Sm, Eu, Ho, and Lu) are listed in Table S1, † in which the ‘imbalance’ phenomenon of L II also exists.…”

Experimental and Theoretical Studies on Selective Separation of Nd from La/Ce/Pr Using [Omim][DOP]

“…These interactions contribute to the synergistic effect of anions and cations of ILs for efficient extraction of Nd(III). 30 Effect of Equilibrium Time and I/A. To investigate the minimum time to reach extraction equilibrium, the effect of [Omim][DOP] on the E of Nd(III) under different contact times was studied.…”

“…The interactions between three ILs and Nd­(III) include strong attraction and VDW interaction, while the VDW interaction and strong steric effect exist within the ILs. These interactions contribute to the synergistic effect of anions and cations of ILs for efficient extraction of Nd­(III) …”