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[Display omitted] • Et-Tol-DAPhen displayed strong extractability and excellent selectivity for Pd2+in HNO 3 solution. • The ratio of Pd2+ to the ligand in the extracted species was determined. • The single-crystal of Et-Tol-DAPhen·Pd(NO 3) 2 was obtained for the first time. • A neutral complexation extraction model was determined. The solvent extraction of Pd2+ in nitric acid solution by a phenanthroline-derived diamide ligand of N,N′ -diethyl- N,N′ -ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen) and the complexation between them were described. By using meta -nitrobenzotrifluoride (F-3) as a diluent, Et-Tol-DAPhen ligand extracted Pd2+ with strong extractability and excellent selectivity in comparison with traditional amine extractants Aliquat 336 nitrate and tri- n -octylamine. Job's method and mole ratio method suggested the formation of a 1:1 complex of Pd2+ with Et-Tol-DAPhen. The extraction was a spontaneous and exothermic process of decreased entropy. Furthermore, the analyses of Fourier transform infrared spectra (FT-IR), UV-vis titration, and single-crystal X-ray diffraction revealed that the composition of the extracted species was [Et-Tol-DAPhen·Pd(NO 3) 2 ]. Based on the results of solvent extraction and complexation study, a neutral complexation extraction model was proposed. Meanwhile, the stability constant for the complexation of Pd2+ with Et-Tol-DAPhen was also presented. [ABSTRACT FROM AUTHOR]

[Display omitted] • A-PzPy showed good selectivity of Am3+ over Eu3+ without any lipophilic anion source. • A-PzPy could effectively separate Am3+ from Eu3+ at a wide molar acidity range. • The composition of complexes was determined by coordination study. • A neutral complexation extraction mechanism was determined. The synthesis, Eu3+ complexation, and selective solvent extraction of Am3+ over Eu3+ in nitric acid solution by 2-carboxamido-6-(1 H -pyrazol-3-yl)-pyridines (A-PzPy) ligands were described. Without the aid of any lipophilic anion source, A-PzPy ligands in methyl isobutyl ketone (MIBK) diluent demonstrated a more favorable affinity of Am3+ than Eu3+ at high acidity levels. Slope analysis showed the formation of 1:2 metal/ligand extracted species. The extraction was a spontaneous exothermic process. The analyses of fluorescence titration, Fourier transform infrared (FT-IR), Raman, time-resolved laser fluorescence spectrum (TRLFS), electrospray ionization mass spectrometry (ESI-MS), conductivity and microcalorimetric titration revealed that the composition of complex is [Eu(NO 3) 2 (H 2 O)∙2(Et- p -Tol-A-PzPy)](NO 3). Combining the results of solvent extraction and complexation study, the extraction mechanism was proposed. Furthermore, the stability constants (log β) and thermodynamic parameters (Δ H , Δ S , Δ G) for complexation of Eu3+ with Et- p -Tol-A-PzPy were also presented. [ABSTRACT FROM AUTHOR]