2010/09/17 by D. Girnt, Peter W. Roesky, Andreas Geist +3 · 54 citations
Chemistry · Engineering · Environmental Science · #Absorption spectroscopy #Actinide #Chelation #Chemical Synthesis and Characterization #Chemistry #Equilibrium constant #Europium #Extended X-ray absorption fine structure #Extraction and Separation Processes #Inorganic chemistry #Ion #Lanthanide #Ligand (biochemistry) #Organic chemistry #Physical chemistry #Radioactive element chemistry and processing #Selectivity
paper · open access · doi:10.1021/ic101309j
published in Inorganic Chemistry 49(20), 9627-9635 (American Chemical Society)
openalex publication_date 2010/09/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/02
With the aim of better understanding the selectivity of the established system 2,6-ditriazinylpyridine (BTP) for actinide(III)/lanthanide(III) separations, a related model system was synthesized and studied. The N donor complexing ligand 6-(3,5-dimethyl-1H-pyrazol-1-yl)-2,2'-bipyridine (dmpbipy) was synthesized having a fused N heterocycle ring structure modified from the BTP partitioning ligand, and its extraction performance and selectivity for trivalent actinide cations over lanthanides was evaluated. X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS), and time-resolved laser fluorescence spectroscopy (TRLFS) results show that 1:1 complexes are formed, unlike the 1:3 complex for BTP systems. The equilibrium constant for curium complex formation with dmpbipy was determined to be log K = 2.80, similar to that for nitrate. The Gibbs free energy, ΔG(20 °C), of 1:1 Cm-dmpbipy formation in n-octan-1-ol was measured to be -15.5 kJ/mol. The dmpbipy ligand in 1-octanol does not extract Am(III) Eu(III) from HNO(3) but was found to extract Am(III) with limited selectivity over Eu(III) (SF(Am(III)/Eu(III)) ≈ 8) dissolved in 2-bromohexanoic acid and kerosene at pH > 2.4.