Sergentu Dumitru-Claudiu, Teze David, Sabatié-Gogova Andréa, Alliot Cyrille, Guo Ning, Bassal Fadel, Silva Isidro Da, Deniaud David, Maurice Rémi, Champion Julie, Galland Nicolas, Montavon Gilles
SUBATECH, UMR CNRS 6457, IN2P3/EMN Nantes/Université de Nantes, 4 rue Alfred Kastler, BP 20722, 44307, Nantes Cedex 3, France.
CEISAM, UMR CNRS 6230, Université de Nantes, 2 rue de la Houssinière, BP 92208, 44322, Nantes Cedex 3, France.
Chemistry. 2016 Feb 24;22(9):2964-71. doi: 10.1002/chem.201504403. Epub 2016 Jan 15.
It is generally assumed that astatide (At(-) ) is the predominant astatine species in basic aqueous media. This assumption is questioned in non-complexing and non-reductive aqueous solutions by means of high-pressure anion-exchange chromatography. Contrary to what is usually believed, astatide is found to be a minor species at pH=11. A different species, which also bears a single negative charge, becomes predominant when the pH is increased beyond 7. Using competition experiments, an equilibrium constant value of 10(-6.9) has been determined for the formation of this species from AtO(OH) with the exchange of one proton. The identification of this species, AtO(OH)2 (-) , is achieved through relativistic quantum mechanical calculations, which rule out the significant formation of the AtO2 (-) species, while leading to a hydrolysis constant of AtO(OH) in excellent agreement with experiment when the AtO(OH)2 (-) species is considered. Beyond the completion of the Pourbaix diagram of astatine, this new information is of interest for the development of (211) At radiolabeling protocols.
一般认为，砹化物（At(-) ）是碱性水介质中主要的砹物种。通过高压阴离子交换色谱法，在非络合和非还原水溶液中对这一假设提出了质疑。与通常的看法相反，发现在pH = 11时砹化物是次要物种。当pH值增加到7以上时，另一种同样带有单个负电荷的物种成为主要物种。通过竞争实验，确定了由AtO(OH)通过一个质子交换形成该物种的平衡常数为10(-6.9) 。通过相对论量子力学计算实现了对该物种AtO(OH)2 (-) 的鉴定，该计算排除了AtO2 (-) 物种的大量形成，同时当考虑AtO(OH)2 (-) 物种时，得出的AtO(OH)水解常数与实验结果非常吻合。除了完成砹的Pourbaix图外，这一新信息对于开发（211）At放射性标记方案具有重要意义。
