Scrutinizing “Invisible” astatine: A challenge for modern density functionals

Abstract

The main-group 6p elements did not receive much attention in the development of recent density functionals. In many cases it is still difficult to choose among the modern ones a relevant functional for various applications. Here, we illustrate the case of astatine species (At, Z = 85) and we report the first, and quite complete, benchmark study on several properties concerning such species. Insights on geometries, transition energies and thermodynamic properties of a set of 19 astatine species, for which reference experimental or theoretical data has been reported, are obtained with relativistic (two-component) density functional theory calculations. An extensive set of widely used functionals is employed. The hybrid meta-generalized gradient approximation (meta-GGA) PW6B95 functional is overall the best choice. It is worth noting that the range-separated HSE06 functional as well as the old and very popular B3LYP and PBE0 hybrid-GGAs appear to perform quite well too. Moreover, we found that astatine chemistry in solution can accurately be predicted using implicit solvent models, provided that specific parameters are used to build At cavities. © 2016 Wiley Periodicals, Inc.

Towards a Stronger Halogen Bond Involving Astatine: Unexpected Adduct with Bu3PO Stabilized by Hydrogen Bonding

“…Indeed, the molecular structure(s)c an readily be determined from the (experimental) stoichiometry of acompound, as well as many other spectroscopic signatures at ad esired level of accuracy.I nt his work, the twocomponent relativistic density functionalt heory (DFT) approach is used, as in previous successful works. [11,22] According to the former benchmark study focused on astatine species, the B3LYP [23] hybrid functional appears as as afe cost-effective choice, [24] whichi sa lso true for describing astatine-mediated halogen bonds. [11] The calculated value of log K BAtI is 4.37 at the B3LYP/AVDZ [13] level of theory,i ne xcellent agreement with the experimental one.…”

On the Interplay between Charge‐Shift Bonding and Halogen Bonding

“…[42,44,[48][49][50][51][52][53] For instance, the interaction energy of At-mediated XBs can be affected by SOC effects up to 35 %. Nevertheless, many studies have demonstrated that the quantum calculations should also include the relativistic spin-orbit interaction for At-containing compounds.…”

The bonding picture in hypervalent XF3 (X = Cl, Br, I, At) fluorides revisited with quantum chemical topology

“…The effective core potential (ECP)‐based spin‐orbit DFT method was selected for the 2c‐DFT computations which handle on an equal footing electron correlation and SOC during the variational treatment. The applied density‐functional approximation is the PBE0 hybrid functional, whose applicability was recently assessed on the XF 3 systems under study . For the ClF 3 system, only all‐electron NR‐DFT calculations were performed while SR‐DFT and 2c‐DFT computations were performed on the remaining systems using small‐core ECP n MDF pseudopotentials.…”

“…The applied density-functional approximation is the PBE0 hybrid functional, [51] whose applicability was recently assessed on the XF 3 systems under study. [8,52] For the ClF 3 system, only all-electron NR-DFT calculations were performed while SR-DFT and 2c-DFT computations were performed on the remaining systems using smallcore ECPnMDF pseudopotentials. The pseudopotentials that overcome the absence of the n 5 10, 28, and 60 inner-core electrons have been used for the Br, I, and At atoms, respectively.…”