Advances on the Determination of the Astatine Pourbaix Diagram: Predomination of AtO(OH)2 (-) over At(-) in Basic Conditions - PubMed (original) (raw)

. 2016 Feb 24;22(9):2964-71.

doi: 10.1002/chem.201504403. Epub 2016 Jan 15.

David Teze 1 2, Andréa Sabatié-Gogova 1, Cyrille Alliot 3, Ning Guo 1, Fadel Bassal 2, Isidro Da Silva 4, David Deniaud 2, Rémi Maurice 1, Julie Champion 1, Nicolas Galland 5, Gilles Montavon 6

Affiliations

Advances on the Determination of the Astatine Pourbaix Diagram: Predomination of AtO(OH)2 (-) over At(-) in Basic Conditions

Dumitru-Claudiu Sergentu et al. Chemistry. 2016.

Abstract

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.

Keywords: Pourbaix diagrams; astatine; competition experiments; hydrolysis constants; quantum mechanical calculations.

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PubMed Disclaimer

Similar articles

Cited by

Publication types

LinkOut - more resources