Towards a Stronger Halogen Bond Involving Astatine: Unexpected Adduct with Bu3PO Stabilized by Hydrogen Bonding |
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| Authors: | Lu Liu Dr Ning Guo Dr Julie Champion Dr Jérôme Graton Dr Gilles Montavon Dr Nicolas Galland Dr Rémi Maurice |
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| Institution: | 1. SUBATECH, UMR CNRS 6457, IN2P3/IMT Atlantique/Université de Nantes, 4 rue Alfred Kastler, BP 20722, 44307 Nantes Cedex 3, France;2. CEISAM, UMR CNRS 6230, Université de Nantes, 2 rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France |
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| Abstract: | The halogen bond is a powerful tool for the molecular design and pushing the limits of its strength is of major interest. Bearing the most potent halogen-bond donor atom, astatine monoiodide (AtI) was recently successfully probed Nat. Chem. 2018 , 10, 428–434]. In this work, we continue the exploration of adducts between AtI and Lewis bases with the tributylphosphine oxide (Bu3PO) ligand, revealing the unexpected experimental occurrence of two distinct chemical species with 1:1 and 2:1 stoichiometries. The 1:1 Bu3PO⋅⋅⋅AtI complex is found to exhibit the strongest astatine-mediated halogen bond so far (with a formation constant of 10(4.24±0.35)). Quantum chemical calculations unveil the intriguing nature of the 2:1 2Bu3PO⋅⋅⋅AtI adduct, involving a halogen bond between AtI and one Bu3PO molecular unit plus CH⋅⋅⋅O hydrogen bonds chelating the second Bu3PO unit. |
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| Keywords: | astatine competition experiments density functional calculations halogens halogen bonds hydrogen bonds |
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