6-(3,5-Dimethyl-1H-pyrazol-1-yl)-2,2′-bipyridine as ligand for Actinide(III)/Lanthanide(III) separation

• Verfasst von: Girnt, Denise [VerfasserIn]
• Verfasst von: Roesky, Peter [VerfasserIn]
• Verfasst von: Geist, Andreas [VerfasserIn]
• Verfasst von: Ruff, Christian [VerfasserIn]
• Verfasst von: Panak, Petra [VerfasserIn]
• Verfasst von: Denecke, Melissa Anne [VerfasserIn]
• Titel: 6-(3,5-Dimethyl-1H-pyrazol-1-yl)-2,2′-bipyridine as ligand for Actinide(III)/Lanthanide(III) separation
• Verf.angabe: Denise Girnt, Peter W. Roesky, Andreas Geist, Christian M. Ruff, Petra J. Panak, and Melissa A. Denecke
• E-Jahr: 2010
• Jahr: June 30, 2010
• Umfang: 9 S.
• Fussnoten: Gesehen am 28.03.2023
• Titel Quelle: Enthalten in: Inorganic chemistry
• Ort Quelle: Washington, DC : American Chemical Society, 1962
• Jahr Quelle: 2010
• Band/Heft Quelle: 49(2010), 20, Seite 9627-9635
• ISSN Quelle: 1520-510X
• DOI: doi:10.1021/ic101309j
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1840326018

Abstract

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 HNO3 but was found to extract Am(III) with limited selectivity over Eu(III) (SFAm(III)/Eu(III) ≈ 8) dissolved in 2-bromohexanoic acid and kerosene at pH > 2.4.