Periodicity, Electronic Structures, and Bonding of Gold Tetrahalides [AuX₄]⁻ (X = F, Cl, Br, I, At, Uus)

Abstract

Systematic theoretical and experimental investigations have been performed to understand the periodicity, electronic structures, and bonding of gold halides using tetrahalide [AuX4](-) anions (X = F, Cl, Br, I, At, Uus). The [AuX4](-) (X = Cl, Br, I) anions were experimentally produced in the gas phase, and their negative-ion photoelectron spectra were obtained, exhibiting rich and well-resolved spectral peaks. As expected, Au-X bonds in such series contain generally increasing covalency when halogen ligands become heavier. We calculated the adiabatic electron detachment energies as well as vertical electron detachment energies using density functional theory methods with scalar relativistic and spin-orbit coupling effects. The computationally simulated photoelectron spectra are in good agreement with the experimental ones. Our results show that the trivalent Au(III) oxidation state becomes progressively less stable while Au(I) tends to be preferred when the halides become heavier along the Periodic Table. This series of molecules provides an example for manipulating the oxidation state of metals in complexes through ligand design.

Revealing the Self‐Degradation Mechanisms in Methylammonium Lead Iodide Perovskites in Dark and Vacuum

“…Our results suggested that the I 2 − ions diffusion even occurred in dark conditions, might due to its low‐activation energy. Here, the charged AuI 2 − species do exist in a quasi‐linear complex with mixed valence states, suppressed the distribution of Au 3 − ions that could alter the work function and creates deep traps states that degrade the device stability . The mechanism of AuI 2 − formation and iodine diffusion is schematically represented in TOC.…”

Electron density properties and metallophilic interactions of gold halides AuX2and Au2X (X = F–I):Ab Initiocalculations

“…Metal clusters have attracted much experimental and theoretical research interest in the past few decades. Certain clusters consisting of a metal atom surrounded by electronegative atoms can display “superatom” behavior . These clusters, also known as “superhalogens,” can possess electron affinities (EA) that are even larger than that of a Cl atom, which has the highest EA in the periodic table.…”

“…Certain clusters consisting of a metal atom surrounded by electronegative atoms can display "superatom" behavior. [1][2][3][4][5][6][7][8][9] These clusters, also known as "superhalogens," can possess electron affinities (EA) that are even larger than that of a Cl atom, which has the highest EA in the periodic table. Their size and composition can be controlled and they imitate the properties of an atom.…”

“…In their study, energy decomposition analysis, natural resonance theory, and ELF analyses show an increased covalent character of Au-X interactions from F to Uus. [5,6] Our previous research on AuX (X 5 F-At) [9] clearly demonstrates that natural bond orbital (NBO) analysis, [16,17] topological analyses on electron density properties, ELF, [18] bond critical point (BCP), Laplacian, electrostatic potential (ESP), [19] and atoms in molecules (AIM) theory [20] are powerful tools to provide more detailed information about chemical interactions.…”

AuRnX and XAuRn (X=F ‐ I and OH)

“…An excellent review by Bellert and Breckenridge suggested that the XeAu + is described by a covalent bonding through an electrostatic model, while the nature of other NGAu + interactions is left undecided. Meanwhile, CM‐halides have also attracted many interests in terms of both experimental and theoretical investigations . Generally, the metal‐halides show ionic bonding characteristics.…”