The Complexation of Cm(III) with Succinate Studied by Time-Resolved Laser Fluorescence Spectroscopy and Quantum Chemical Calculations

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• 作者：Daniel R. Fröhlich ; Michael Trumm ; Andrej Skerencak-Frech ; Petra J. Panak
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：May 2, 2016
• 年：2016
• 卷：55
• 期：9
• 页码：4504-4511
• 全文大小：447K
• 年卷期：0
• ISSN：1520-510X

文摘

The complexation of Cm(III) with succinate in an aqueous NaCl solution was studied as a function of ionic strength, ligand concentration, and temperature using time-resolved laser fluorescence spectroscopy (TRLFS). After the Cm(III) speciation was determined by peak deconvolution, the temperature-dependent thermodynamic stability constants (log K<sub class="stack">nsub><sup class="stack">0sup>(T)) were determined for the stepwise formation of [CmSuc<sub>nsub>]<sup>3–2nsup> (n = 1–3) in the temperature range 20–80 °C (n = 3 only when T ≥ 50 °C) using the specific ion interaction theory (SIT). The first and second complexation steps show an endothermic behavior, as the respective standard reaction enthalpies (Δ<sub>rsub>H<sub class="stack">msub><sup class="stack">0sup>) and entropies (Δ<sub>rsub>S<sub class="stack">msub><sup class="stack">0sup>) derived from the integrated van’t Hoff equation are positive. These TRLFS results are complemented by quantum chemical calculations to resolve the molecular structure of the formed Cm(III) complexes. The results show that the formation of a seven-membered chelate ring is the favored conformation of [CmSuc<sub>nsub>]<sup>3−2nsup> (n = 1−3).