Gutmann's Donor and Acceptor Numbers for Ionic Liquids and Deep Eutectic Solvents

Area of Science:

• Chemistry
• Materials Science

Background:

• Ionic liquids (ILs) and deep eutectic solvents (DES) are versatile materials with tunable properties.
• Understanding their Lewis acid/base characteristics is crucial for predicting their behavior in chemical reactions.

Purpose of the Study:

• To propose an experimental and computational methodology for analyzing the Lewis acid/base responses of ILs and DES.
• To establish a correlation between binding enthalpy and experimental data for predicting solvent properties.

Main Methods:

• Utilized Viktor Gutmann's concepts of donor (DN) and acceptor (AN) numbers.
• Employed antimony pentachloride (SbCl5) as a probe in dichloroethane.
• Recorded experimental data using UV-Vis spectroscopy for various ILs and DES.
• Validated the donor number (DN) model using benchmark reactions.

Main Results:

• Demonstrated good correlations between binding enthalpy and experimental data.
• The proposed approach serves as a first approximation for predicting H-bonding abilities of new ILs and DES.
• Identified limitations in modeling the electron acceptor number (AN) for a complete description of polarity.

Conclusions:

• The developed methodology provides a valuable tool for assessing Lewis acid/base properties of ILs and DES.
• Further refinement is needed to fully capture the polarity of these solvents.
• The study offers insights into the reactivity of systems in these neoteric solvents.