Stability and instability of the isoelectronic UO2(2+) and PaO2+ actinyl oxo-cations in aqueous solution from density functional theory based molecular dynamics.
Stability and instability of the isoelectronic UO2(2+) and PaO2+ actinyl oxo-cations in aqueous solution from density functional theory based molecular dynamics.
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基于密度泛函理论的分子动力学研究水溶液中等电子 UO2(2 ) 和 PaO2 锕基氧代阳离子的稳定性和不稳定性。
DOI：
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发表时间：
2011
影响因子：
3.3
通讯作者：
P. Vitorge
中科院分区：
文献类型：
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作者：
R. Spezia;B. Siboulet;S. Abadie;R. Vuilleumier;P. Vitorge
本文采用基于密度泛函理论(DFT)的分子动力学模拟方法(CPMD)研究了PA(V)在液态水中的单正离子，并与它们的U(VI)等电子配位进行了比较，以了解PA(V)在水溶液中的特殊化学行为。四种不同的PA(V)单阳离子异构体在液态水中似乎是稳定的：[PaO(2)(H(2)O)(5)](+)(AQ)、[PA(OH)(4)(H(2)O)(2)](+)(AQ)、[PAO(OH)(2)(H(2)O)(4)](+)(AQ)和[PA(OH)(4)(H(2)O)(3)](+)(AQ)。另一方面，在U(VI)的情况下，只有铀酰[UO(2)(H(2)O)(5)](2)(+)(AQ)是稳定的。含有取代一个或两个氧键的羟基的其他物种很容易转化为铀酰。PA-OH键是稳定的，但在U-OH中突然断裂。这使得在水中形成各种不同的PA(V)物种成为可能，并参与了它在水溶液中的独特化学行为。此外，与U(VI)相反，在水中这两个光化氧正离子在氧原子为PA(V)形成稳定的和扩展的H-键网络的能力上是不同的。具体地说，发现前列腺素的每个氧原子有2到3个氢键，而铀酰的氢键在0到1之间。
In this work, Pa(V) monocations have been studied in liquid water by means of density functional theory (DFT) based molecular dynamic simulations (CPMD) and compared with their U(VI) isoelectronic counterparts to understand the peculiar chemical behavior of Pa(V) in aqueous solution. Four different Pa(V) monocationic isomers appear to be stable in liquid water from our simulations: [PaO(2)(H(2)O)(5)](+)(aq), [Pa(OH)(4)(H(2)O)(2)](+)(aq), [PaO(OH)(2)(H(2)O)(4)](+)(aq), and [Pa(OH)(4)(H(2)O)(3)](+)(aq). On the other hand, in the case of U(VI) only the uranyl, [UO(2)(H(2)O)(5)](2)(+)(aq), is stable. The other species containing hydroxyl groups replacing one or two oxo bonds are readily converted to uranyl. The Pa-OH bond is stable, while it is suddenly broken in U-OH. This makes possible the formation of a broad variety of Pa(V) species in water and participates to its unique chemical behavior in aqueous solution. Further, the two actinyl oxocations in water are different in the ability of the oxygen atoms to form stable and extended H-bond networks for Pa(V) contrary to U(VI). In particular, protactinyl is found to have between 2 and 3 hydrogen bonds per oxygen atom while uranyl has between zero and one.