Hybrid donor extractants are a promising class of compounds for the separation of trivalent actinides and lanthanides. Here, we investigated a series of sterically loaded diphosphonate ligands based on bipyridine (BiPy-PO-iPr and BiPy-PO-cHex) and phenanthroline (Phen-PO-iPr and Phen-PO-cHex). We studied their complex formation with nitrates of trivalent f-elements in solvent extraction systems (Am and Eu) and homogeneous acetonitrile solutions (Nd, Eu, and Lu). Phenanthroline extractants demonstrated the highest efficiency and selectivity [SF(Am/Eu) up to 14] toward Am­(III) extraction from nitric acid solutions among all of the studied diphosphonates of N-heterocycles. The binding constants established by UV–vis titration also indicated stronger binding of sterically impaired diphosphonates compared to the primary substituted diphosphonates. NMR titration and slope analysis during solvent extraction showed the formation of 2:1 complexes at high concentrations (>10–3 mol/L) for phenanthroline-based ligands. According to UV–vis titrations at low concentrations (10–5–10–6 mol/L), the phenanthroline-based ligands formed 1:1 complexes. Bipyridine-based ligands formed 1:1 complexes regardless of the ligand concentration. Luminescence titrations revealed that the quantum yields of the complexes with Eu­(III) were 81 ± 8% (BiPy-PO-iPr) and 93 ± 9% (Phen-PO-iPr). Single crystals of the structures [Lu­(μ2,κ4-(iPrO)2P­(O)­Phen­(O)2(OiPr))­(NO3)2]2 and Eu­(Phen-PO-iPr)­(NO3)3 were obtained by chemical synthesis with the Phen-PO-iPr ligand. X-ray diffraction studies revealed a closer contact of the f-element with the aromatic N atoms in the case of sterically loaded PO ligands compared with sterically deficient ligands. Density functional theory calculations allowed us to rationalize the observed selectivity trends in terms of the bond length, Mayer bond order, and preorganization energy.

The fractionation of high-level radioactive waste from nuclear power plants simplifies the handling of its components, and facilitates the reduction of radiotoxic effects on the environment. The search and study...

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Hybrid chiral molecules containing frameworks of a pregnane steroid and 5‐arylpyrrolidine‐2,4‐dicarboxylate have been synthesized for the first time in a diastereomerically pure form. Chiral pregnane‐based acrylate induced stereoselective formation of all‐cis trisubstituted pyrrolidine moiety under cycloaddition with stabilized N‐metalated azomethine ylides. β‐Dipeptidic fragment was built up at C‐3 pregnane position using consequent acryloylation and stereoselective cycloaddition with stabilized N‐metalated azomethine ylide. All novel hybrid molecules demonstrated micromolar cytotoxic activity against human cervical epithelioid cancer HeLa cell culture in native and estradiol‐stimulated forms and breast carcinoma MCF‐7 cell culture. The most of hybrid compounds are less toxic towards human skin fibroblasts HSF as compared with studied hormonal tumor cells.

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