The Nature of Bonding between Argon and Mixed Gold–Silver Trimers

Abstract

The controversial nature of chemical bonding between noble gases and noble metals is addressed. Experimental evidence of exceptionally strong Au-Ar bonds in Ar complexes of mixed Au-Ag trimers is presented. IR spectra reveal an enormous influence of the attached Ar atoms on vibrational modes, particularly in Au-rich trimers, where Ar atoms are heavily involved owing to a relativistically enhanced covalency. In Ag-rich trimers, vibrational transitions of the metal framework predominate, indicating a pure electrostatic character of the Ag-Ar bonds. The experimental findings are analyzed by means of DFT calculations, which show how the relativistic differences between Au and Ag are manifested in stronger Au-Ar binding energies. Because of the ability to vary composition and charge distribution, the trimers serve as ideal model systems to study the chemical nature of the bonding of noble gases to closed-shell systems containing gold.

Noble‐Noble Strong Union: Gold at Its Best to Make a Bond with a Noble Gas Atom

“…reported the Ar tagged gold silver mixed clusters studied via both experimentally and theoretically. While in the first paper, they showed the drastic change in the binding behavior towards Ar in moving from Ag 3 + →Ag 2 Au + →Au 3 + . In Ag 3 + cluster, the Ar atoms were only weakly tagged and the basic cluster was eventually unperturbed by the messenger Ar atoms.…”

“…In 2015, in two separate papers published almost at the same time, Shayeghi et al [74] reported the Ar tagged gold silver mixed clusters studied via both experimentally and theoretically. While in the first paper, [74a] they showed the drastic change in the binding behavior towards Ar in moving from Ag 3 + !Ag 2 Au + !Au 3 + .…”

Optical Absorption of Small Palladium‐Doped Gold Clusters

“…This is confirmed by the calculated Ar evaporation energies that are of the order of 0.2 eV only (Table 1), in agreement with previous calculations. [44] Actually the experiments show that the absorption of a photon by the Au 4 + Ar cluster leads to simultaneous evaporation of an Ar and an Au atom, as shown in Figure 1b. This is consistent with the low calculated energy required for this process (1.54 eV).…”

An Argon–Oxygen Covalent Bond in the ArOH+ Molecular Ion

“…[19] Recent examples of spectroscopically characterized ions with substantial bonding to argon include gold-silver trimers and boroxol rings of several sizes. [20] The strongly bound ArH + ion is well known in mass spectrometry and has been detected in the Crab Nebula, opening the field of interstellar noble gas chemistry. [21] TheA rOH + cation, also ap otential interstellar molecule, [22] was seen in ICP mass spectrometry and found to be kinetically stable towards reaction with H 2 .…”