Insights from quantum chemical calculations into inner and outer-sphere complexation of plutonium(<scp>iv</scp>) by monoamide and carbamide extractants

Failali, Abdelmounaim; Acher, Eléonor; Vallet, Valérie; Réal, Florent; Guillaumont, Dominique

doi:10.1039/d0cp05363e

Cited by 2 publications

(3 citation statements)

References 37 publications

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“…For the pure DEHBA extractant, the hydrodynamic radius of Ce(IV) is about 13 Å. This value is larger (factor 2.5) than the one estimated to be 7.75 Å by NMR (28,29) and theoretical calculations (25) for Pu(NO 3 ) 4 (DEHBA) 2 in dilute medium ([DEHBA] < 1 mol.L À 1 ). This difference can be explained by the existence of a hydrogen bonding network between the solvates Ce IV (NO 3 ) 4 (DEHBA) n and the DEHBA molecules in the pure solvent, whereas in dilute medium (< 1 mol.L À 1 ) the solvates are isolated.…”

Section: Cyclic Voltammetry Of Ce(iv) In Nn-das Equilibrated With Aqu...mentioning

confidence: 74%

“…However, few fundamental studies have been reported, and the influence of the structure of N,N-dialkylamides on the extraction properties is not yet fully explained. The structures of Pu(IV) and U(VI) complexes with N,Ndialkyl amides ligands were recently characterized by Guillaumont and coworkers [24,25] using single-crystal Xray diffraction (XRD), extended X-ray absorption fine structure (EXAFS), and theoretical calculations. These studies show that these species are tetra-nitrato complexes solvated by two extractants.…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical Behavior of Ce(IV)/Ce(III) Couple in N,N‐Di(2‐ethylhexyl)‐n‐butanamide (DEHBA), N,N‐Di(2‐ethylhexyl)‐iso‐butanamide (DEHiBA), and N,N‐Di(2‐ethylhexyl)‐3,3‐dimethyl Butanamide (DEHDMBA)

et al. 2021

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In this work we report on the electrochemical behavior of Ce(IV)/Ce(III) redox couple in pure N,N‐dialkyl amides (N,N‐DA), namely N,N‐di(2‐ethylhexyl)‐n‐butanamide (DEHBA), N,N‐di(2‐ethylhexyl)‐iso‐butanamide (DEHiBA), and N,N‐di(2‐ethylhexyl)‐3,3‐dimethyl butanamide (DEHDMBA) equilibrated with nitric aqueous solutions as an entry to the direct electrochemical characterization of plutonium in these extractants. Ce(IV)/Ce(III) redox process was used as a model. Its potential (E1/2≅1.02 V/SCE) is not affected by the temperature and the nature of the N,N‐DA and this clearly indicates that the functionalities of these extractants produce the same relative effect on both +IV and +III oxidation states of the cerium cation. Linear variations of the current intensity of the reduction peak of Ce(IV) with the concentration of Ce(IV)/N,N‐DAs/HNO3(5 M) solutions were obtained from cyclic voltammograms recorded at 25 °C and 40 °C. Due to the poor definition of the voltammograms in DEHiBA and DEHDMBA, such characterization allows only the evaluation of the performances of the chemical extraction of Ce(IV) from aqueous nitric acid solution by the undiluted DEHBA. To our knowledge, the electrochemical behavior of Ce(IV)/Ce(III) in N,N‐DAs was not previously studied and our findings will for sure open the door for further investigations in this field.

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Section: Cyclic Voltammetry Of Ce(iv) In Nn-das Equilibrated With Aqu...mentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Electrochemical Behavior of Ce(IV)/Ce(III) Couple in N,N‐Di(2‐ethylhexyl)‐n‐butanamide (DEHBA), N,N‐Di(2‐ethylhexyl)‐iso‐butanamide (DEHiBA), and N,N‐Di(2‐ethylhexyl)‐3,3‐dimethyl Butanamide (DEHDMBA)

et al. 2021

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“…Failali et al . indeed showed that steric hindrance of a monoamide destabilizes the complex Pu(NO 3 ) 4 L 2 when the acyl chain was branched [39] . By rending the inner spheres complexes formation less favorable, this steric hindrance would therefore be responsible of the Pu extraction decrease.…”

Section: Resultsmentioning

confidence: 99%

Stereo‐ and Regiochemical Effect of N,N‐Dialkylamide Extractants on the Speciation of Pu Complexes

Lemire,

Dumas,

Marie

et al. 2023

Eur J Inorg Chem

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The relationship between extractant stereochemistry and their extraction performance has only poorly been established. In order to address a part of this concern, we investigated the Pu(IV) liquid‐liquid extraction (LLE) by using the N,N‐di‐(2‐ethylhexyl)butyramide (DEHBA), as well as those of its position isomers. DEHBA (ββ‐isomer) and N‐(2‐ethylhexyl)‐N‐(oct‐3‐yl)butyramide (EHOBA or αβ‐isomer) were synthesized as a mixture of stereoisomer or stereoenriched (R,S)‐ and (S,S)‐diastereoisomers, and were all assessed for PuIV LLE. The results showed that both the position and the stereoisomerism of the aliphatic substituents affect PuIV complexation and extraction. We found that Pu extraction is lowered by factor 2 to 4 when the ethyl branching group is closer to the complexing site. UV‐vis spectroscopy showed that this extraction decrease was affected by steric hindrance inducing a deprivation of Pu inner sphere complex. Effect of stereoisomerism is highlighted for branching closer to the complexing site (α‐position). Enantiopure DEHBA stereoisomers provided similar Pu extraction, whereas a slight decrease could be noticed for the more cluttered stereoenriched (αβ)‐isomers, which was also concomitant with a smaller population of inner sphere complex. In contrast, the stereoisomers mixture led to a strong decrease of Pu extraction because of an antagonistic association in the mixed complexes.

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Insights from quantum chemical calculations into inner and outer-sphere complexation of plutonium(iv) by monoamide and carbamide extractants

Abstract: The strong influence of the structure of amide derivatives on plutonium extraction properties is rationalized from DFT calculations.

Cited by 2 publications

References 37 publications

Electrochemical Behavior of Ce(IV)/Ce(III) Couple in N,N‐Di(2‐ethylhexyl)‐n‐butanamide (DEHBA), N,N‐Di(2‐ethylhexyl)‐iso‐butanamide (DEHiBA), and N,N‐Di(2‐ethylhexyl)‐3,3‐dimethyl Butanamide (DEHDMBA)

Electrochemical Behavior of Ce(IV)/Ce(III) Couple in N,N‐Di(2‐ethylhexyl)‐n‐butanamide (DEHBA), N,N‐Di(2‐ethylhexyl)‐iso‐butanamide (DEHiBA), and N,N‐Di(2‐ethylhexyl)‐3,3‐dimethyl Butanamide (DEHDMBA)

Stereo‐ and Regiochemical Effect of N,N‐Dialkylamide Extractants on the Speciation of Pu Complexes

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