Seventeen‐Coordinate Actinide Helium Complexes

Abstract

Abstract:The geometries and electronic structures of molecular ions featuring He atoms complexed to actinide cations are explored computationally using density functional and coupled cluster theories. A new record coordination number is established, as AcHe17 3+ , ThHe17 4+ and PaHe17 4+ are all found to be true geometric minima, with the He atoms clearly located in the first shell around the actinide. Analysis of AcHen 3+ (n = 1-17) using the Quantum Theory of Atoms in Molecules (QTAIM) confirms these systems as having closed shell, charge-induced dipole bonding. Excellent correlations (R 2 > 0.95) are found between QTAIM metrics (bond critical point electron densities and delocalisation indices) and the average Ac-He distances, and also with the incremental He binding energies.

Computer-Assisted Design of Macrocyclic Chelators for Actinium-225 Radiotherapeutics

“…Actinium has been characterized using EXAFS structural data of Ac 3+ with water, HCl, NO 3 – , and DOTP 8– , and NMR studies have been performed of Ac 3+ with chelators (DOTP 8– ). − , In studies with water, HCl, and NO 3 – , the preferred coordination number (CN) of Ac 3+ was shown to be between 9 and 11. There is also a computational study that predicts that coordination numbers of 17 can be reached with very small ligands, like helium atoms . These studies motivated our study of the preferred coordination number of Ac 3+ with macrocyclic chelators.…”

“…There is also a computational study that predicts that coordination numbers of 17 can be reached with very small ligands, like helium atoms. 40 These studies motivated our study of the preferred coordination number of Ac 3+ with macrocyclic chelators.…”

“…A major challenge facing computer-assisted design of Ac 3+ chelators lies in the fact that there is currently little knowledge about which molecules coordinate strongly to actinium and even less understanding of why certain molecules form stable complexes with the ion. ,− The purpose of this paper is to computationally explore interactions between macrocyclic chelating molecules and Ac 3+ . Particular focus is paid to developing an understanding of which factors lead to strong Ac 3+ binding and using this knowledge to develop rational design principles for Ac 3+ radiotherapeutics.…”

Actinium Hydrides AcH10, AcH12, and AcH16 as High-Temperature Conventional Superconductors

“…9 Recently, another exciting property of Ac, formation of polycations AcHe 17 3+ with helium, was predicted. 10 This is closely related to synthesis and study of polyhydrides (e.g., XH 16 ) as a particular case of polyatomic complexes and its stabilization by pressure or charge.…”

Al(He)³⁺^N Clusters:A Theoretical Study

“…'helium' is the most unreactive because of its high ionization energy of 577 kcal mol -1 (or 25 eV) 1 . Based on density functional theory and high-level ab initio method, Kaltsoyannis 2 predicted the formation of 17 coordinate helium-actinide complexes. This is surprising because in spite of having very high ionization energy, helium is still able to form complexes with metals.…”