An expanded halogen bonding scale using astatine

Abstract

As a non-covalent interaction, halogen bonding is now acknowledged to be useful in all fields where the control of intermolecular recognition plays a pivotal role. Halogen-bond basicity scales allow to...

In vivo stability of 211At-radiopharmaceuticals: on the impact of halogen bond formation

“…4,24,34,35 In particular, this method has enabled us to establish the first halogen-bond basicity scale that is specific to astatine, pK BAtI . 20 It combines the equilibrium constants measured for the complexation between astatine monoiodide (AtI) and sixteen neutral Lewis bases. The pK BAtI scale culminates with N,N,N′,N′-tetramethylthiourea (TMTU) as the strongest XB acceptor, particularly in comparison with the nucleophilic sites of selected neutral amino acids (Chart 2).…”

“…We recently reported the first experimental characterization of XBs mediated by astatine. 24 The technique we have since extended enables measurements in aqueous and hydrophobic media (two extremes for a biological environment), 20 and it can be applied to characterize XBs with the nucleophilic sites representative of those of neutral amino acids. To compensate for the lack of suitable spectroscopic tools, 20,21,24 DFT modelling has been used to obtain information on these interactions at the molecular level.…”

“…24 The technique we have since extended enables measurements in aqueous and hydrophobic media (two extremes for a biological environment), 20 and it can be applied to characterize XBs with the nucleophilic sites representative of those of neutral amino acids. To compensate for the lack of suitable spectroscopic tools, 20,21,24 DFT modelling has been used to obtain information on these interactions at the molecular level. The contributions of molecular modelling to the field of medicinal chemistry are well recognized, [26][27][28] and, in particular, DFT calculations allow precise quantification of At-mediated XBs with anionic sites of amino acids.…”

Tailoring an efficient computational methodology for studying ligand interactions with heavy radiometals in solution: the case of radium

“…A recent tour de force was the identification, assisted by quantum mechanical calculations, of the very first halogen bonds involving astatine. 1,2 The Pourbaix diagram (potential-pH) of this radioelement could also not have been established without coupling modelling to experiments. 3,4 Among other recent examples, it is the comparison of the spectral signatures with those from theoretical calculations which allowed to conclude on the nature of the predominant forms of polonium(IV) in concentrated hydrochloric acid solution.…”

Pourbaix Diagram of Astatine Revisited: Experimental Investigations

“…The reported investigations of the chemical forms of astatine remain based on limited technical approaches. Some knowledge of astatine species was acquired according to (i) their behaviors in coprecipitation experiments, electromobility measurements, thin-layer chromatography measurements, and competition experiments in a biphasic system and (ii) comparisons with iodine chemistry. , These sketchy analyses are insufficient for determining the exact nature of the species involved in many reactions, with occasional inconsistencies in the literature. , A more detailed analysis of the data, however, allows the tracing back of important information such as the charge, , the stoichiometry of the species, , and quantitative data describing the formation of the species. − Molecular modeling has also proven to be of great help because it can provide extra information at the molecular level and quantitative data that can be compared with experimental values. − The nature of the studied species can be assessed through such a comparison.…”