Abstract
Fundamental to the field of ionic liquids is the understanding that structure begets function. In this work, we reported the development of thioether-based ionic liquids, with enhanced hydrophobicity and low melting point (Tm), via the thiol‒yne reaction. Cationic lipids can simply be converted to macroscopically hydrophobic ionic liquids by replacing their native chloride counteranion with Tf2N. Features that specifically increase or decrease fluidity are identified by juxtaposing the wide-ranging Tm values of these highly lipophilic salts with elements of their cation structures. Most importantly, when these Tm-increasing and -decreasing features are incorporated into the same cation, an “averaged” Tm value is observed. These findings may prove to be elements of the “know-how” needed to design functional ionic liquids that liquefy within relatively predictable temperature ranges.
•We developed a class of dual thioether branch ionic liquids via the thiol‒yne click reaction.•The new amphiphilic ionic liquids are [Tf2N]‒ salts of previously reported lipofection agents.•We provided valuable design insights into engineering their structure-property relationships.