A spectroscopic study of Cm(III) complexation with propionate in saline solutions at variable temperatures

• Verfasst von: Fröhlich, Daniel R. [VerfasserIn]
• Verfasst von: Skerencak-Frech, Andrej [VerfasserIn]
• Verfasst von: Morkos, Marie-Louise Karin [VerfasserIn]
• Verfasst von: Panak, Petra [VerfasserIn]
• Titel: A spectroscopic study of Cm(III) complexation with propionate in saline solutions at variable temperatures
• Verf.angabe: Daniel R. Fröhlich, Andrej Skerencak-Frech, Marie-Louise K. Morkos and Petra J. Panak
• E-Jahr: 2013
• Jahr: 01 Mar 2013
• Umfang: 9 S.
• Teil: volume:37
• Teil: year:2013
• Teil: number:5
• Teil: pages:1520-1528
• Teil: extent:9
• Fussnoten: Gesehen am 07.06.2021
• Titel Quelle: Enthalten in: New journal of chemistry
• Ort Quelle: London : RSC, 1987
• Jahr Quelle: 2013
• Band/Heft Quelle: 37(2013), 5, Seite 1520-1528
• ISSN Quelle: 1369-9261
• DOI: doi:10.1039/C3NJ00109A
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1759945110

Abstract

The complexation of Cm(III) with propionate is studied by time resolved laser fluorescence spectroscopy (TRLFS) in saline solutions (NaCl and CaCl2) as a function of ionic strength, ligand concentration, and temperature. The molar fractions of the different Cm(III) species are determined by peak deconvolution of the measured fluorescence spectra. By using the specific ion interaction theory (SIT), the stability constants at zero ionic strength (log K0n) of the first and second complexation steps are determined. The stability constants of the mono- and dipropionate complexes increase continuously with increasing temperature between 20-90 °C in both background electrolytes. The log K0n values are linearly correlated to the reciprocal temperature, indicating ΔrH0m = const. and ΔrC0p,m = 0. Therefore, the thermodynamic constants (ΔrH0m, ΔrS0m, ΔrG0m) for the formation of the [Cm(Prop)]2+ and [Cm(Prop)2]+ complexes are derived from the integrated van't Hoff equation. The results show that both reactions are entropy driven. Furthermore, neither the formation of ternary species including Ca2+ nor a complexing effect of Cl− at elevated temperatures is observed under the chosen experimental conditions. Lastly, the ion-ion interaction coefficients of both complexed species with Cl− are derived for the first time.