CEISAM, UMR CNRS 6230, Université de Nantes, 2 Rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France.
J Phys Chem B. 2013 May 2;117(17):5206-11. doi: 10.1021/jp401759p. Epub 2013 Apr 12.
The AtO(+) molecular ion, a potential precursor for the synthesis of radiotherapeutic agents in nuclear medicine, readily reacts in aqueous solution with organic and inorganic compounds, but at first glance, these reactions must be hindered by spin restriction quantum rules. Using relativistic quantum calculations, coupled to implicit solvation models, on the most stable AtO(+)(H2O)6 clusters, we demonstrate that specific interactions with water molecules of the first solvation shell induce a spin change for the AtO(+) ground state, from a spin state of triplet character in the gas phase to a Kramers-restricted closed-shell configuration in solution. This peculiarity allows rationalization of the AtO(+) reactivity with closed-shell species in aqueous solution and may explain the differences in astatine reactivity observed in (211)At production protocols based on "wet" and "dry" processes.
AtO(+)分子离子是核医学中合成放射性治疗药物的潜在前体，它很容易在水溶液中与有机和无机化合物发生反应，但乍一看，这些反应肯定受到自旋限制量子规则的阻碍。我们使用相对论量子计算，结合隐式溶剂化模型，对最稳定的 AtO(+)(H2O)6 团簇进行了计算，证明了与第一溶剂化壳层水分子的特定相互作用会导致 AtO(+)基态的自旋发生变化，从气相中的三重态自旋态转变为溶液中的受限闭壳层构型。这种特殊性可以解释 AtO(+)在水溶液中与闭壳层物质的反应性，并可能解释基于“湿”和“干”过程的 (211)At 生产方案中观察到的砹反应性差异。
