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The extraction and complexation behavior of soft–hard combined N,N-dialkyl-1,10-phenanthroline-2-amide (PTA) ligands with Am(iii) and Eu(iii) in HNO3 solution was investigated. The effects of acidity of the aqueous solution, shaking time, concentration of the extractant and temperature on the distribution ratios were studied. The extraction ability for both Am(iii) and Eu(iii) was found to decrease with an increase in the length of the substituent alkyl chains, and the highest extractability and selectivity for Am(iii) over Eu(iii) were found for the diethyl-substituted ligand. The separation factor for Am(iii) over Eu(iii) reached around 7.6 at low acidity and high salinity. UV-vis titrations revealed that the dialkyl-substituted tridentate PTAs all predominantly formed 1 : 1 complexes with Eu(iii), which agreed well with the results of slope analyses in the extraction experiments. The stability constants (KEuL) as well as the protonation constants (KH) were also determined by UV-vis titration. Computational chemistry gave a good explanation of the relationship between the alkalinity and the protonation energy of the proposed PTA ligands. Density functional theory (DFT) calculations on the optimized structures of Am(iii) and Eu(iii) complexes with C2-PTA showed that the selectivity may originate from differences in the degree of covalency of the bonds between the metal ions and the donor N atoms, which fits well with the experimental results. [ABSTRACT FROM AUTHOR]

Short-lived ruthenium and rhodium isotopes were produced from a 252Cf spontaneous fission (SF) source. Their volatile carbonyl complexes were formed in gas-phase reactions in situ with the carbon-monoxide containing gas. A gas-jet system was employed to transport the volatile carbonyls from the recoil chamber to the chemical separation apparatus. The gas-phase chemical behaviors of these carbonyl complexes were studied using an online low temperature isothermal chromatography (IC) technique. Long IC columns made up of FEP Teflon were used to obtain the chemical information of the high-volatile Ru and Rh carbonyls. By excluding the influence of precursor effects, short-lived isotopes of 109–110Ru and 111–112Rh were used to represent the chemical behaviours of Ru and Rh carbonyls. Relative chemical yields of about 75% and 20% were measured for Ru(CO)5 and Rh(CO)4, respectively, relative to the yields of KCl aerosols transported in Ar gas. The adsorption enthalpies of ruthenium and rhodium carbonyl complexes on a Teflon surface were determined to be around ΔHads = –33+1−2 kJ mol−1 and −36+2−1 kJ mol−1, respectively, by fitting the breakthrough curves of the corresponding carbonyl complexes with a Monte Carlo simulation program. Different from Mo and Tc carbonyls, a small amount of oxygen gas was found to be not effective for the chemical yields of ruthenium and rhodium carbonyl complexes. The general chemical behaviors of short-lived carbonyl complexes of group VI–IX elements were discussed, which can be used in the future study on the gas-phase chemistry of superheavy elements – Bh, Hs, and Mt carbonyls. [ABSTRACT FROM AUTHOR]