Аннотация:Reprocessing of spent nuclear fuel (SNF) is an important task ina frame of ecology and rational use of natural resources. Uranium, as the maincomponent of SNF (>95%), can be recovered for further use as fresh nuclearfuel. To minimize an amount of solid radioactive waste generated during SNFreprocessing, new extractants are under investigation. Diamides of 1,10-phenanthroline-2,9-dicarboxylic acid are perspective tetradentate N-donorligands that form strong complexes with f-elements, which are soluble in polarorganic solvents. As an example of three ligands of this class, we conducted acomparative study and showed how the substituent in the amide functionalgroup affects the extraction ability toward uranyl nitrate from nitric acid media.We have performed a careful study (NMR, FT-IR, XRD, RMC-EXAFS) of thestructures of synthesized complexes of new ligands with uranyl nitrate and usedquantum mechanical calculations to explain the discovered regularities through.