Spectroscopic Studies on the Thermodynamics of the Complexation of Trivalent Curium with Propionate in the Temperature Range from 20 to 90 °C

Skerencak, Andrej; Höhne, Stefanie; Hofmann, Sascha; Marquardt, Christian; Panak, Petra J.

doi:10.1007/s10953-012-9945-x

Cited by 10 publications

(20 citation statements)

References 28 publications

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“…There, Δ r H 0 m = 5-8 kJ mol −1 and Δ r S 0 m = 80-93 for the first complexation reaction and Δ r H 0 m = 33-44 kJ mol −1 and Δ r S 0 m = 140-173 J K −1 mol for the second complexation reaction were determined. 21,22 These values are again in very good agreement with the results of the present study. Δ r H 0 m values for the formation of [Cm(Ac) 3 ] are in a comparable range as for the second complexation reaction but show a significantly larger error which is due to the high relative uncertainty of the corresponding stability constants (see Table 2).…”

Section: Thermodynamic Datasupporting

confidence: 92%

“…There, log K 0 1 and log K 0 2 increased from 3.2-3.4 to 3.5-3.7 and 1.5-1.8 to 2.6-2.9, respectively, when the temperature was increased from 20 to 90 °C. 21,22 These values are in excellent agreement with the stability constants in the present work. Literature data for the acetate complexes of Am(III) ([Am(Ac) n ] 3−n , n = 1-3) at T = 25 °C are given in the NIST database 46.6 (log K 0 1 = 2.60, log K 0 2 = 1.79, log K 0 3 = 0.60).…”

Section: Thermodynamic Datasupporting

confidence: 91%

“…Detailed information on the calculation of [Ac − ] eq is found in the ESI † and in the literature. 21,22 The calculated free ligand concentrations and the Cm(III) speciation determined via peak deconvolution at different temperatures are used to calculate the conditional stability constants for the stepwise formation of [Cm(Ac) n ] 3−n (n = 1-3) at a given ionic strength according to eqn (1):…”

Section: Thermodynamic Datamentioning

confidence: 99%

“…The same trend was observed for the interaction of Cm(III) with propionate. 21,22 Experimental section…”

Section: Introductionmentioning

confidence: 99%

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A spectroscopic study on the formation of Cm(iii) acetate complexes at elevated temperatures

2014

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The complexation of Cm(III) with acetate is studied by time resolved laser fluorescence spectroscopy (TRLFS) as a function of ionic strength, ligand concentration, temperature and background electrolyte (NaClO4, NaCl and CaCl2 solution). The speciation of Cm(III) is determined by peak deconvolution of the emission spectra. To obtain the thermodynamic stability constants (log K) for the formation of [Cm(Ac)n](3-n) (n = 1-3), the experimental data are extrapolated to zero ionic strength according to the specific ion interaction theory (SIT). The results show a continuous increase of the stability constants with increasing temperature (20-90 °C). The standard reaction enthalpies and entropies (ΔrH, ΔrS) of the respective reactions are derived from the integrated Van't Hoff equation. The results show that all complexation steps are endothermic and thus entropy driven (ΔrH and ΔrS > 0).

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Section: Thermodynamic Datasupporting

confidence: 92%

Section: Thermodynamic Datasupporting

confidence: 91%

Section: Thermodynamic Datamentioning

confidence: 99%

“…The same trend was observed for the interaction of Cm(III) with propionate. 21,22 Experimental section…”

Section: Introductionmentioning

confidence: 99%

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A spectroscopic study on the formation of Cm(iii) acetate complexes at elevated temperatures

2014

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“…Such a temperature-dependent decrease of the emission intensity has already been reported for Cm-propionate in NaClO 4 solution. 17 A similar effect is also observed for the interaction between Cm(III) and H 2 O, 18 F À , 19 and NO 3 À 20 in aqueous solution. As described by Tian et al, this effect is attributed to the increasing thermal population of higher energetic levels of the Cm(III) ion.…”

Section: Fluorescence Spectrasupporting

confidence: 52%

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

et al. 2013

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The complexation of Cm(III) with propionate is studied by time resolved laser fluorescence spectroscopy (TRLFS) in saline solutions (NaCl and CaCl 2 ) 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 K 0 n ) 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 1C in both background electrolytes. The log K 0 n values are linearly correlated to the reciprocal temperature, indicating D r H 0 m = const. and D r C 0 p,m = 0. Therefore, the thermodynamic constants (D r H 0 m , D r S 0 m , D r G 0 m ) 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 Ca 2+ nor a complexing effect of Cl À at elevated temperatures is observed under the chosen experimental conditions. Lastly, the ion-ion interaction coefficients of both complexed species with Cl À are derived for the first time.

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Complex formation of Cm(III) with formate studied by time-resolved laser fluorescence spectroscopy

Fröhlich

Skerencak-Frech

Panak

2015

Applied Geochemistry

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Spectroscopic Studies on the Thermodynamics of the Complexation of Trivalent Curium with Propionate in the Temperature Range from 20 to 90 °C

Cited by 10 publications

References 28 publications

A spectroscopic study on the formation of Cm(iii) acetate complexes at elevated temperatures

A spectroscopic study on the formation of Cm(iii) acetate complexes at elevated temperatures

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

Complex formation of Cm(III) with formate studied by time-resolved laser fluorescence spectroscopy

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