Molecular design principles of ionic liquids with a sulfonyl fluoride moiety

Abstract

The continued success of ionic liquids in applications ranging from energy to medicine poses the challenge to rapidly find new functional ionic liquids with desirable properties while developing practical, scalable syntheses. As a SuFExable functionality, the sulfonyl fluoride has become widely adopted throughout the field of chemical biology due, in part, to its unique stability–reactivity pattern, highlighting the underappreciated potential of the S^VI–F motif in materials chemistry. For the first time, we herein report the development of a set of sulfonyl fluoride-functionalized ionic liquids with considerable structural diversity via an efficient, modular, and orthogonal fluorosulfonylethylation procedure. The resulting SO₂F-functionalized ionic milieu has properties consistent with its classification as ionic liquids. We employed a combination of molecular design, synthesis, computational modeling, and X-ray crystallographic studies to gain in-depth understanding of their structure–property correlations. The diversification of the SO₂F-bearing salts is extended to include active pharmaceutical precursors, allowing for access to functional materials with a priori low toxicity.