Investigation of Astatine(III) Hydrolyzed Species: Experiments and Relativistic Calculations

Champion, Julie; Sabatié-Gogová, Andrea; Bassal, Fadel; Ayed, Tahra; Alliot, Cyrille; Galland, Nicolas; Montavon, Gilles

doi:10.1021/jp3099413

Cited by 52 publications

(79 citation statements)

References 36 publications

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“…Two anionic species, A and B, were characterized by retention times of 5.2 min and 8.1 min, respectively, with a roughly 1:99 ratio between these two species (see Figure , top). The minor species, A, was identified as At − by comparison of retention times of samples prepared in the conditions in which this species assuredly predominates, both at neutral and acidic pH in reducing conditions.…”

Section: Resultsmentioning

confidence: 99%

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

Sergentu

Tezé

Sabatié-Gogová

et al. 2016

Chemistry A European J

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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.

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Section: Resultsmentioning

confidence: 99%

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

Sergentu

Tezé

Sabatié-Gogová

et al. 2016

Chemistry A European J

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“…11 Among the recent experimental highlights, it is worth quoting the determination of the ionization potential of the free atom, 12 or the determination of predominance domains in the Pourbaix diagram (E-pH) of At in aqueous solution. [13][14][15] One should also mention the theoretical prediction of a metallic behavior for condensed astatine, unlike the other halogens. 16 Furthermore, stable At cationic forms (At + and AtO + ) exist in aqueous solution and their coordination chemistry has been experimentally explored by reporting complexation constants with various inorganic ligands.…”

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confidence: 99%

Effective bond orders from two-step spin–orbit coupling approaches: The I2, At2, IO+, and AtO+ case studies

Maurice

Réal

Gomes

et al. 2015

The Journal of Chemical Physics

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The nature of chemical bonds in heavy main-group diatomics is discussed from the viewpoint of effective bond orders, which are computed from spin-orbit wave functions resulting from contracted spin-orbit configuration interaction calculations. The reliability of the relativistic correlated wave functions obtained in such two-step spinorbit coupling frameworks is assessed by benchmark studies of the spectroscopic constants with respect to either experimental data, or state-of-the-art fully relativistic correlated calculations. The I 2 , At 2 , IO + , and AtO + species are considered, and differences and similarities between the astatine and iodine elements are highlighted.In particular, we demonstrate that spin-orbit coupling weakens the covalent character of the bond in At 2 even more than electron correlation, making the consideration of spin-orbit coupling compulsory for discussing chemical bonding in heavy (6p) main group element systems.

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“…Studies by other investigators on the redox chemistry of astatine have shown that under oxidizing and acidic pH conditions, AtO+ (At +3 hydroxide species) might be also present [18–20]. Although it possibly could be a component of the At(1) peak, its presence becomes important only at pH much lower than those present in our experiments [21].…”

Section: Resultsmentioning

confidence: 52%

Radiopharmaceutical chemistry of targeted radiotherapeutics, part 4: Strategies for 211At labeling at high activities and radiation doses of 211At α-particles

Pozzi

Zalutsky

2017

Nuclear Medicine and Biology

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Introduction Alpha particles are radiation of high energy and short range, properties that can lead to radiolysis-mediated complications in labeling chemistry at the high radioactivity levels required for clinical application. In previous papers in this series, we have shown that radiation dose has a profound effect on the astatine species that are present in the labeling reaction and their suitability for the synthesis of N-succinimidyl 3-[211At]astatobenzoate. The purpose of this study was to evaluate the effects of adding N-chlorosuccinimide (NCS) to the methanol solution used for initial isolation of 211At after distillation, a process referred to as 211At stabilization, on 211At chemistry after exposure to high radiation doses. Methods High performance liquid chromatography was used to evaluate the distribution of 211At species present in methanol in the 500–65,000 Gy radiation dose range and the synthesis of SAB from N-succinimidyl 3-(tri-n-butylstanny)benzoate in the 500–120,000 Gy radiation dose range using different 211At time activity combinations under conditions with/without 211At stabilization. Results In the absence of NCS stabilization, a reduced form of astatine, At(2), increased with increasing radiation dose, accounting for about half the total activity by about 15,000 Gy, while with stabilization, At(2) accounted for <10% of 211At activity even at doses >60,000 Gy. SAB yields without stabilization rapidly declined with increasing dose, falling to ~20% at about 5,000 Gy while with stabilization, yields >80% were obtained with 211At solutions stored for more than 23 h and receiving radiation doses >100,000 Gy. Conclusions Adding NCS to the methanol solution used for initial isolation of 211At is a promising strategy for countering the deleterious effects of radiolysis on 211At chemistry. Advances in Knowledge and Implications for Patient Care This strategy could facilitate the ability to perform 211At labeling at sites remote from its production and at the high activity levels required for clinical applications.

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Investigation of Astatine(III) Hydrolyzed Species: Experiments and Relativistic Calculations

Cited by 52 publications

References 36 publications

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

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

Effective bond orders from two-step spin–orbit coupling approaches: The I2, At2, IO+, and AtO+ case studies

Radiopharmaceutical chemistry of targeted radiotherapeutics, part 4: Strategies for 211At labeling at high activities and radiation doses of 211At α-particles

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Investigation of Astatine(III) Hydrolyzed Species: Experiments and Relativistic Calculations

Cited by 52 publications

References 36 publications

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

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

Effective bond orders from two-step spin–orbit coupling approaches: The I2, At2, IO+, and AtO+ case studies

Radiopharmaceutical chemistry of targeted radiotherapeutics, part 4: Strategies for 211At labeling at high activities and radiation doses of 211At α-particles

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

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