Solvent extraction of U(VI), Th(IV), Am(III) and lanthanides(III) from aqueous nitric acid solutions with 1,2,3-triazole–modified carbamoylmethylphosphine oxide (L) and [C₄mim][Tf₂N] ionic liquid dissolved in 1,2-dichloroethane was studied. A considerable synergistic effect in this system was observed. This effect is associated with the high hydrophobicity of the IL anions which participate in the formation of metal extracted ion species. The influence of aqueous and organic phases on the extraction efficiency was elucidated and stoichiometry of the complexes extracted was determined. The synergistic effect for metal ion extraction from aqueous nitric acid solutions with compound L and [C₄mim][Tf₂N] in 1,2-dichloroethane becomes weaker when the acidity of the aqueous phase increases. The partition of Tf₂N⁻ anions between the organic and aqueous phases is the major factor governing the extractability of metal ions in the L – IL synergistic system. The interaction of L with HTf₂N and HNO₃ also substantially affects the efficiency of metal ion extraction.

Using the methodology of “click” chemistry, a singular method has been developed for the synthesis of unique conjugates based on sesquiterpene lactones: dehydrocostuslactone and alantolactone with polyalkoxybenzenes. To expand the structural range of the resulting conjugates, the length of the 1,2,3-triazole spacer was varied. For all synthesized compounds, the cytotoxic profile was determined on the cell lines of tumor origin (SH-SY5Y, HeLa, Hep-2, A549) and normal Hek 293 cells. It was found that the compounds based on alantolactone 7a–d with a long spacer and substances containing dehydrocostuslactone 10a–d with a short spacer have the greatest toxic effect. The decrease in cell survival under the action of these conjugates may be due to their ability to cause dissipation of the transmembrane potential of mitochondria and inhibit the process of glycolysis, leading to cell death. The obtained results confirm the assumption that the development of conjugates based on sesquiterpene lactones and polyalkoxybenzenes can be considered as a promising strategy for the search for potential antitumor agents.

The extraction of lanthanides(III) from nitric acid solutions in the systems involving novel functionalized ionic liquids based on cationic carbamoyl(methyl)phosphine oxide (CMPO) derivatives and dinonylnaphthalenesulfonate anions in molecular diluents was studied. The stoichiometry of the Ln(III) extracted species was determined using slope analysis. The influence of the concentration of HNO₃ in the aqueous phase and the nature of organic diluents on the metal ion extraction efficiency into the organic phase was considered. Functionalized ionic liquids 1-[3-[[(diphenylphosphinyl)acetyl]amino]propyl]-1H-imidazol-1-ium dinonylnaphthalenesulfonate (L¹HA) and 1-[2-[[(diphenylphosphinyl)acetyl]amino]ethyl]-pyridin-2-ium dinonylnaphthalenesulfonate (L²HA) demonstrate higher extraction ability towards Ln(III) than their neutral CMPO analog, diphenylphosphorylacetic acid N-nonylamide (L).

A novel bis(methylimidazolium) ionic liquid 3,3′-(pentane-1,5-diyl) bis(1-methylimidazolium) bis(trifluoromethanesulfonul)imide [C₅(mim)₂][Tf₂N]₂ has been synthesized. Its effect on the extraction of U(VI), Th(IV), Am(III), and lanthanides(III) from nitric acid solutions with a polydentate neutral bis(carbamoylmethylphosphine oxide) ligand L containing two bidentate fragments Ph₂P(O)CH₂C(O)NH–, interconnected by 4,7,10-trioxatridecane spacer through amide nitrogen atoms has been investigated. The efficiency of the extraction of metal ions with solutions of L in 1,2-dichloroethane (DCE) significantly increases in the presence of [C₅(mim)₂][Tf₂N]₂. A synergistic effect in the extraction of metal ions in this system has been explained with the high hydrophobicity of the Tf₂N⁻ anions, which are involved in the formation of extracted complexes as counterions. The value of the synergistic effect decreases with increasing acidity of the aqueous phase. The influence of the composition of the aqueous and organic phases on the efficiency of the extraction of metal ions into the organic phase is considered, and the stoichiometry of the extracted complexes is determined. The effect of the HTf₂N coextraction with L on the extraction of metal ions in the L – [C₅(mim)₂][Tf₂N]₂ system is discussed. The synergistic effect in the extraction of Ln(III) from 3 M HNO₃ solutions with the mixture of L and [C₅(mim)₂][Tf₂N]₂ in DCE is higher than that in the L – [C₄mim][Tf₂N] – DCE system.

Modified extractants, carbamoylmethylphosphine oxides Ph₂P(O)CH₂CON(R)CH₂P(O)Ph₂ (R = Et, i-Pr, Bu, Oct), containing a phosphoryl group in the amide part of the molecule, have been synthesized. The extraction of microquantities of REE(III), U(VI), and Th(IV) with solutions of the obtained extractants in organic solvents from nitric acid solutions has been studied. The stoichiometry of the extractable complexes was determined, and the influence of the extractant structure, the organic diluent nature, and the aqueous phase composition on the efficiency and selectivity of the U(VI), Th(IV), and REE(III) extraction into the organic phase was considered. It has been shown that the modification of diphenyl(N,N-dialkylcarbamoylmethyl)phosphine oxide by introducing an additional coordinating group CH₂P(O)Ph₂ into the amide part of the molecule leads to an increase in the efficiency of heavy REE(III) extraction and a decrease in the efficiency of light REE(III), and also Th(IV) and U(VI) extraction from nitric acid solutions. The degree of REE(III), U(VI), and Th(IV) extraction into the organic phase by the carbamoylmethylphosphine oxides increases significantly in the presence of the ionic liquid 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide.

A method for modifying sesquiterpene lactones using the click chemistry methodology has been developed. A series of conjugates of alantolactone and dehydrocostus lactone with alkoxy substituted benzylazides was obtained and their cytotoxic profile with respect to tumor cells of the A549, SH-SY5Y, Hep-2 and HeLa lines was evaluated. It has been shown that derivatives containing dehydrocostus lactone motif in their structure exhibit the highest cytotoxic activity.