Janicki Rafał, Lindqvist-Reis Patric
University of Wrocław, Faculty of Chemistry, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
Dalton Trans. 2018 Feb 13;47(7):2393-2405. doi: 10.1039/c7dt04836j.
The structural and spectroscopic properties of the compounds [C(NH)][Gd:M(CO)(HO)]·0.75HO (1) and [C(NH)][Y:M(CO)]·2HO (2) (M = Eu, Cm) were determined. The crystals contain differently hydrated tetracarbonate complexes, [M(CO)(HO)] and [M(CO)], which were used as structural and spectroscopic models of Eu(iii) and Cm(iii) tetracarbonate species in aqueous solutions. The luminescence spectra of the crystals were used to establish the stoichiometry and stability of the limiting species of the aqueous Eu(iii) and Cm(iii) carbonate systems at different temperatures and in a broad range of ionic strengths. By implementing this method together with the Pitzer approach used for the description of highly concentrated systems, it was possible to determine the thermodynamic functions of the reaction [Eu(CO)] + CO ⇆ [Eu(CO)] under standard conditions for the first time (ΔH° = 31.4 ± 2 kJ mol and ΔS° = 82 ± 10 J mol K). The proposed model for Eu(iii) carbonates is consistent with the data recorded for the Cm(iii)-carbonate systems. The presented results are important not only from the point of view of environmental issues, but also for the coordination chemistry of f-elements in general.
测定了化合物[C(NH₂)₃][Gd:M(CO₃)₄(H₂O)₂]·0.75H₂O (1)和[C(NH₂)₃][Y:M(CO₃)₄]·2H₂O (2)（M = Eu、Cm）的结构和光谱性质。晶体中含有不同水合程度的四碳酸盐配合物[M(CO₃)₄(H₂O)₂]和[M(CO₃)₄]，它们被用作水溶液中Eu(iii)和Cm(iii)四碳酸盐物种的结构和光谱模型。利用晶体的发光光谱确定了不同温度和广泛离子强度下水溶液中Eu(iii)和Cm(iii)碳酸盐体系极限物种的化学计量和稳定性。通过将该方法与用于描述高浓度体系的皮泽方法相结合，首次在标准条件下确定了反应[Eu(CO₃)₃] + CO₂ ⇆ [Eu(CO₃)₄]的热力学函数（ΔH° = 31.4 ± 2 kJ mol⁻¹和ΔS° = 82 ± 10 J mol⁻¹ K⁻¹）。所提出的Eu(iii)碳酸盐模型与Cm(iii) - 碳酸盐体系记录的数据一致。所呈现的结果不仅从环境问题的角度来看很重要，而且对于一般f元素的配位化学也很重要。
