A Homoleptic KrF₂ Complex, [Hg(KrF₂ )₈ ][AsF₆ ]₂ ⋅2 HF

Area of Science:

• Inorganic Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Noble gas compounds, particularly those involving krypton, are rare and challenging to synthesize.
• Understanding the coordination behavior of noble gases with metal centers is crucial for expanding chemical frontiers.

Purpose of the Study:

• To synthesize and characterize the first homoleptic krypton difluoride (KrF2) coordination complex.
• To investigate the bonding interactions and structural properties of a novel metal-KrF2 complex.

Main Methods:

• Reaction of mercury(II) hexafluoroarsenate (Hg(AsF6)2) with a large excess of KrF2 in anhydrous hydrogen fluoride (HF).
• Low-temperature crystal structure determination of the resulting complex, [Hg(KrF2)8][AsF6]2·2HF.
• Raman spectroscopy and computational studies (DFT) to analyze vibrational frequencies and bonding.

Main Results:

• Successful synthesis of the first homoleptic KrF2 coordination complex, [Hg(KrF2)8][AsF6]2·2HF.
• Isolation and structural characterization of the [Hg(KrF2)8]2+ dication, featuring eight KrF2 ligands coordinated to Hg2+ in a square-antiprismatic geometry.
• Raman spectra assigned using calculated gas-phase vibrational frequencies, confirming the complex's structure.
• Computational studies revealed the significance of both electrostatic and orbital interactions in metal-ligand bonding.

Conclusions:

• The study demonstrates the feasibility of forming stable coordination complexes with KrF2 as a ligand.
• The findings provide valuable insights into the bonding nature and structural characteristics of noble gas-metal interactions.
• This work opens new avenues for exploring the chemistry of noble gas compounds and their potential applications.