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Structural and magnetic susceptibility characterization of Pu(V) aqua ion using sonochemistry as a facile synthesis method
Inorganic Chemistry Frontiers ( IF 6.1 ) Pub Date : 2017-10-16 00:00:00 , DOI: 10.1039/c7qi00389g
Elodie Dalodière 1, 2, 3, 4, 5 , Matthieu Virot 1, 2, 3, 4, 5 , Thomas Dumas 5, 6, 7, 8 , Dominique Guillaumont 5, 6, 7, 8 , Marie-Claire Illy 5, 6, 7, 8 , Claude Berthon 5, 6, 7, 8 , Laëtitia Guerin 5, 6, 7, 8 , André Rossberg 9, 10, 11, 12 , Laurent Venault 5, 6, 7, 8 , Philippe Moisy 5, 6, 7, 8 , Sergey I. Nikitenko 1, 2, 3, 4, 5
Affiliation  

Since the past few years, Pu(V) has gained much attention due to its potential contribution to the environmental migration of actinides. However, the preparation of concentrated (up to mM) and pure Pu(V) solutions is quite difficult and often hindered by its great instability towards disproportionation, thus limiting the accessibility to physical and chemical property data. This work describes the rapid and facile sonochemical preparation of relatively stable Pu(V) solutions in the millimolar range free from the admixtures of the other oxidation states of plutonium. The mechanism deals with the sonochemical reduction of Pu(VI) in weakly acidic perchloric solutions by using the in situ generated H2O2, where the kinetics can be dramatically enhanced under high frequency ultrasound and an Ar/O2 atmosphere. The quasi-exclusive presence of the Pu(V) aqua ion in solution was evidenced by UV-vis absorption spectroscopy. The prepared solutions were found to be stable for more than one month which allowed the accurate XAFS and NMR investigations of Pu(V). EXAFS spectra revealed the presence of two trans dioxo Pu[double bond, length as m-dash]O bonds at 1.81 Å and 4–6 equatorial Pu–Oeq interactions at 2.47 Å characteristic of coordinated water molecules. The exact number of water molecules (N[Oeq(H2O)] = 4) was determined by simulating the EXAFS spectra of the PuO2+ aqua complexes using DFT calculations (geometry and the Debye–Waller factor) and comparing them with experimental signals. For the first time, the magnetic susceptibility of the pentavalent state of plutonium in aqueous solutions was also determined (χM = 16.3 × 10−9 m3 mol−1 at 25 °C) and the related Curie constant was estimated (C = 6.896 × 10−6 m3 K mol−1).

中文翻译:

声化学法简便合成Pu(V)离子的结构和磁化率

过去几年以来,Pu(V)由于其对act系元素向环境迁移的潜在贡献而备受关注。但是,制备浓缩溶液(高达mM)和纯Pu(V)溶液是非常困难的,并且常常因其歧化作用的极大不稳定性而受到阻碍,从而限制了对物理和化学性质数据的访问。这项工作描述了毫摩尔范围内相对稳定的Pu(V)溶液的快速,便捷的声化学制备方法,该溶液不含p的其他氧化态的混合物。该机理涉及通过使用原位生成的H进行声化学还原弱酸性高氯酸溶液中的Pu(VI2 O 2,在高频超声和Ar / O 2气氛下动力学可以显着增强。紫外可见吸收光谱法证实了溶液中存在Pu( V)离子的准排他性。发现所制备的溶液稳定超过一个月,这使得可以对Pu( V)进行准确的XAFS和NMR研究。EXAFS光谱显示,在配位水分子特征为2.47Å时,在1.81Å和4–6赤道Pu-O eq相互作用处存在两个反式二氧代Pu[双键,长度为m-破折号]O键。水分子的确切数目( N [O eq(H 2O)] = 4)是通过使用DFT计算(几何形状和Debye-Waller因子)模拟PuO 2 +水配合物的EXAFS光谱并将其与实验信号进行比较而确定的。对于第一次,在水溶液中钚的五价态的磁化率还测定(χ中号= 16.3×10 -93摩尔-1,在25℃)和相关的居里常数估计(c ^ = 6.896 ×10 -6 m 3 K mol -1)。
更新日期:2017-11-08
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