Halogen-like properties of the Al13 cluster mimicking astatineElectronic supplementary information (ESI) available: Fig. S1 (interhalogen electron population analysis as a function of the Mülliken electronegativity (HPA and NPA)) and Fig. S2 (alkaline halide electron population analysis as a function of the Mülliken electronegativity (HPA and NPA)). See DOI: 10.1039/c8cp00494c

Astatine-211 is considered to be one of the most promising alpha-emitters in targeted alpha therapy (TAT). However, its development has been hindered by its not so well understood chemistry. Hence, any attempt to understanding it better is imperative. Here, we show through DFT calculations that the neutral endohedral Al 13 cluster follows a reactivity pattern very similar to At, more than any other halogen. The halogen and alkali bonding with Al 13 and At presented a strong similarity in their charge transfer processes. Moreover, upon the interchange of At with Al 13 , we found a stable configuration of the compound corresponding to the astatination of aryliodonium salts, which have been considered as possible precursors for the synthesis of 211 At-labeled tracers. Our results provide promising proof of concept that the Al 13 cluster mimics the behaviour of At and might help in better understanding its chemistry and in streamlining the chemical processes of radiolabeling biomolecules. The Al 13 cluster mimics the chemistry of astatine and might help in streamlining the processes of 211 At radiolabeling in targeted alpha therapy (TAT) in cancer treatment.