Hydro-nium bis-(tri-fluoro-methane-sulfon-yl)amide-18-crown-6 (1/1)

Area of Science:

• Crystal structure determination
• Ionic liquid characterization
• Supramolecular chemistry

Background:

• Ionic liquids are salts with low melting points, finding applications in various chemical processes.
• Crown ethers like 18-crown-6 are known for their ability to complex with cations, including hydronium ions.
• Bis-(trifluoromethanesulfonyl)amide is a common weakly coordinating anion used in ionic liquids.

Purpose of the Study:

• To elucidate the detailed crystal structure of the ionic liquid [H3O+][N(SO2CF3)2-][18-crown-6].
• To investigate the hydrogen bonding interactions between hydronium ions, 18-crown-6 molecules, and the bis-(trifluoromethanesulfonyl)amide anion.
• To characterize the conformational behavior and twinning of the ionic liquid crystal.

Main Methods:

• Single-crystal X-ray diffraction at 113 K.
• Analysis of crystallographic data to determine atomic positions and bonding.
• Hydrogen bond distance measurements and analysis of conformational disorder.

Main Results:

• The crystal structure reveals two independent 18-crown-6 molecules, each complexed with a hydronium ion.
• One 18-crown-6 molecule exhibits conformational disorder.
• Hydrogen bonds (O-H⋯O and O-H⋯F) link the hydronium ions to the crown ether and the anion, respectively.
• The crystal is a racemic twin with a component ratio of 0.55:0.45.

Conclusions:

• The study provides a detailed structural understanding of this specific ionic liquid.
• The observed hydrogen bonding network influences the stability and properties of the ionic liquid.
• The conformational disorder and racemic nature are key structural features of this compound.