A rare example of a krypton difluoride coordination compound: [BrOF2][AsF6] x 2 KrF2

Area of Science:

• Inorganic Chemistry
• Solid-State Chemistry
• Quantum Chemistry

Background:

• Previous KrF(2) adducts studied involved transition metals.
• No crystallographic characterization of KrF(2) adducts existed prior to this work.
• Understanding KrF(2) coordination to main-group elements is crucial for novel compound synthesis.

Purpose of the Study:

• To synthesize and structurally characterize a novel KrF(2) adduct with a main-group element.
• To elucidate the bonding nature and charge distribution within the complex.
• To investigate the coordination behavior of KrF(2) with main-group cations.

Main Methods:

• Synthesis of [BrOF(2)][AsF(6)] x 2 KrF(2).
• Low-temperature X-ray crystallography for structural determination.
• Solid-state Raman spectroscopy.
• Quantum-chemical calculations including QTAIM and ELF analyses.

Main Results:

• The first crystallographically characterized KrF(2) adduct with a main-group atom, [BrOF(2)][AsF(6)] x 2 KrF(2), was synthesized.
• KrF(2) ligands coordinate trans to fluorine atoms of the BrOF(2)(+) cation.
• Charge transfer of 0.25 e occurs from KrF(2) and AsF(6)(-) to BrOF(2)(+), with electrostatic interactions dominating.
• Electron lone pair on BrOF(2)(+) is more compact due to coordination.

Conclusions:

• This study provides the first structural evidence of KrF(2) coordinating to a main-group element.
• The bonding is characterized by significant charge transfer and electrostatic interactions.
• The findings offer new insights into the reactivity and coordination chemistry of KrF(2).