Access to pure and highly volatile hydrochalcogenide ionic liquids

Area of Science:

• Inorganic Chemistry
• Materials Science
• Organic Chemistry

Background:

• Ionic liquids (ILs) are versatile solvents with tunable properties.
• Synthesis of hydrosulphide and hydroselenide salts is of general interest.
• Cation-aprotic ILs are a subclass of ILs with specific characteristics.

Purpose of the Study:

• To develop a highly selective synthesis for hydrosulphide and hydroselenide organic salts.
• To investigate the properties of imidazolium hydrochalcogenides derived from methylcarbonate ILs.
• To explore the potential for gas-phase synthesis and crystal growth of these salts.

Main Methods:

• Reaction of methylcarbonate ionic liquids with hydrogen sulfide (H2S) or hydrogen selenide (H2Se).
• Characterization of synthesized salts for purity and definition.
• Investigation of volatility and decomposition using isothermal thermogravimetric analysis (TGA).
• Theoretical analysis using Density Functional Theory (DFT) calculations.

Main Results:

• Achieved highly selective synthesis of analytically pure, well-defined, and soluble hydrosulphide and hydroselenide organic salts.
• Imidazolium hydrochalcogenides demonstrated exceptionally high volatility for cation-aprotic ILs.
• Quantitative sublimation of these salts occurred below 100 °C at 10(-2) mbar.
• Successful ionic single crystal growth from the gas phase was achieved.

Conclusions:

• Methylcarbonate ionic liquids provide an effective route for synthesizing valuable hydrosulphide and hydroselenide salts.
• The high volatility of imidazolium hydrochalcogenides facilitates unique gas-phase processing, including single crystal growth.
• This study opens avenues for novel materials synthesis and purification techniques using ILs.