In this work we report on new examples of phenanthrolindiamides containing asymmetric centers in amide substituents. The synthesized ligands are expected to have complex thermodynamic behavior. Their ...structure was unambiguously confirmed by a combination of spectral analysis methods and X-ray analysis. It is shown that the obtained ligands form complexes with nitrates of rare-earth elements, and the stability constants of such complexes in acetonitrile solution were also measured. The performed solvent extraction tests revealed a significant effect of methyl groups in cyclic amide substituents on the distribution ratios and selectivity factors in the lanthanides(
iii
) and Am(
iii
) series in comparison with the previously studied ligands based on unsubstituted pyrrolidine. The observed effects are explained from the standpoint of quantum chemistry calculations taking into account possible stereoisomerism.
In this work we report on new examples of phenanthrolindiamides containing asymmetric centers in amide substituents.
The management of high-level radioactive waste generated during the reprocessing of spent nuclear fuel in the PUREX process is among of the main problems of modern radiochemistry. This waste contains ...half of the periodic table of elements in the range from As to Cm. To reduce the total radioactivity of the disposed waste, the concept of partioning and transmutation is developed. The implementation of this concept implies the separation of Am(III), Cm(III), and lanthanides(III) from each other. This separation is a complex chemical problem, since these elements have similar physical and chemical properties. In chemical engineering, liquid extraction is considered to be the most suitable method for the separation of Am(III), Cm(III), and lanthanides(III). In this review, we analyzed the published solvent extraction systems, in which americium and lanthanides are separated at the stages of extraction into the organic phase or selective back-extraction from the organic phase by water-soluble complexones. For some extraction systems, dynamic tests carried out over the past 10 years are also described.
In this work, we studied the extraction systems for the separation f-elements based on the tetradentate N,O-donor ligand di(N-ethyl-4-ethylanilide) 2,2′-dipyridyl-6,6′-dicarboxylic acid (L). The ...organic phase of these systems was perspective fluorine-containing organic solvents–metanitrobenzotrifluoride (F-3), ionic liquid C4mimNTf2 (IL), and their mixture. The increase of Am(III) selectivity in the presence of Ln(III) in cases of the diluent mixture was shown. The mechanism of the f-element complexation leading to the improved properties of the extraction systems was studied by UV–visible, Raman-spectroscopy, XRD-study, and density functional theory calculations.
A wide range of 1,10-phenanthroline-2,9-dicarboxylic acid diamides was synthesized, differing in the structure of substituents in the amide function and in the nature of substituents at positions 4 ...and 7 of the heteroaromatic ring. All new compounds were characterized by NMR, IR spectroscopy, and high resolution mass spectrometry. The molecular structure of one of the ligands was unambiguously confirmed by X-ray diffraction analysis. The solubility of all the obtained compounds in 3-nitrobenzotrifluoride was quantitatively evaluated.
The first comprehensive structural and extraction study of a 2,2′-bipyridine-6,6′-dicarboxamide (L diamide) extractant for U, Np, Pu, Th, Am, and Eu ions showed great potential for actinide ...separation due to steric hindrance of the amidic side phenyl ring of the given compound. The study of the complexes of An(VI) and Th(IV) with 2,2′-bipyridyldicarboxamide-type extractants demonstrated the structure of the extraction species for the first time. Investigation of the extraction properties with the radiometric and millimolar quantities of actinides showed similar extraction trends. For the first time, a metal-ion-induced phenyl-ring rotation restriction was found for the U, Th, and Eu complexes by employing temperature-dependent dynamic NMR. A study of the solution behavior of the complexes accompanied by density functional theory modeling studies elucidated the mechanism of the unusual C–N bond rotation restriction induced by metal coordination.
