N,N′-Dialkyl-N,N′-diaryl-1,10-phenanthroline-2,9-dicarboxamides as donor ligands for separation of rare earth elements with a high and unusual selectivity. DFT computational and experimental studies

N,N'-Dialkyl-N,N'-diaryl-1,10-phenanthroline-2,9-dicarboxamides (IV) were predicted (DFT simulation) and then were proved experimentally to be efficient donor ligands with high and unusual selectivity for the extraction separation of lanthanides. Distribution coefficients D of lanthanide cations in two-phase aqueous solution-polar organic solvent decrease with increasing Ln(3+) atomic number. The selectivity factors SFLn1/Ln2 for adjacent lanthanide ions were found to be about 3.