UV–Vis Absorption Spectroscopy of Polonium(IV) Chloride Complexes: An Electronic Structure Theory Study

Abstract

Prepared for Inorg. Chem.

Geometries, interaction energies and bonding in [Po(H2O)n]4+ and [PoCln]4−n complexes

“…When Though it is obvious that the presence of the hydrogen atoms of the water ligands may lower the symmetry, it is actually interesting to note that in some of the cases (n = 4, 5 and 7) quite different structures were obtained. Concerning more specifically the PoCl 4 complex, Stoïanov et al reported in their article 25 a C 2v SPG for the gas-phase structure, with one set of bonds being slightly longer than the other. In fact, we found with our level of theory that the gas phase C 2v structure is only 1.6 kcal mol −1 higher in energy than the T d one, meaning that both are technically possible.…”

“…Note that their first ionization potential value was in good accord with the early value of Charles 10 , and proved to be also in good accord with the yet to come new experimental values derived from two independent experiments 23,24 . In 2019, Stoïanov et al revisited from theory the UV-Vis absorption spectra of polonium chloride complexes 25 . The same year, chalcogen bonding with polonium was examined by Zierkiewicz et al 26 .…”

“…As mentioned before, the +IV oxidation state of polonium dominates in solution. Following the pioneer works of Ayala et al 19 and Stoïanov et al 25 , we will focus on two families of Po(IV)complexes, namely the hydrated [Po(H 2 O) n ] 4+ and the chlorinated [PoCl n ] 4 -n complexes. The first series is of fundamental interest since it relates to the general context of the hydration of heavy-element cations in solution 28 .…”

“…The second series is of practical interest since polonium chloride complexes can form in acidic chloride solutions 12,28 . We will focus on ground-state properties (geometries, interaction energies and bonding descriptors) and assess the dependence of the theoretical results with respect to specific degrees of freedom such as the choice of the correlation method, of the atomic basis sets or for instance of correcting for the basis set superposition error (BSSE) when computing interaction energies, which was not fully done in those earlier works 19,25 . To limit the discussion to pure electronic-structure theory aspects, only gas-phase results will be considered (future work may deal with solvation).…”

Time-Dependent Density Functional Theory Investigation of the UV–Vis Spectra of Organonitrogen Chromophores in Brown Carbon

“…To aid in the interpretation of BrC light absorption, computational chemistry approaches using time-dependent density functional theory (TD-DFT) can be useful to evaluate the light absorption properties of potential BrC chromophores when authentic standards are not available. TD-DFT is a widely used ab initio approach for computing electronic spectra. − The DFT component of TD-DFT computes the electronic structures of atoms, molecules, and solids at ground state, while the TD component accounts for the electronically excited-states of matter when interacting with light . Numerous studies have used TD-DFT to examine optical properties of organic and inorganic dyes in industrial applications such as dye-sensitized solar cells, , textile tinting, and photosensitizers …”