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Numerous non-covalent interactions link together discrete molecules in the crystal structure of the title compound, 2C 20 H 26 N 2 O 2 2+ ·4Cl − ·H 2 O {systematic name: 4-[(5-ethenyl-1-azoniabicyclo[2.2.2]octan-2-yl)(hydroxy)methyl]-6-methoxyquinolin-1-ium dichloride hemihydrate}. A combination of hydrogen bonding between acidic H atoms and the anions in the asymmetric unit forms a portion of the observed hydrogen-bonded network. π–π interactions between the aromatic portions of the cation appear to play a role in the formation of the long-range ordering. One ethylene double bond was found to be disordered. The disorder extends to the neighboring carbon and hydrogen atoms. 

A series of 1,2-dimethylimidazolium ionic liquids bearing a hexadecyl alkyl chain are thoroughly examined via X-ray crystallography. The crystal structures reveal several key variations in the non-covalent interactions in the lipid-like salts. Specifically, distinct cation–cation π interactions are observed when comparing the bromide and iodide structures. Changing the anion to bis(trifluoromethane)sulfonimide (Tf 2 N − ) changes these cation–cation π interactions with anion⋯π interactions. Additionally, several well-defined geometries of the cations are noted based on torsion and core-plane angles of the alkyl chains. Hirshfeld surface analysis is used to distinguish the interactions and geometries in the solid state, helping to reveal characteristic structural fingerprints for the compounds. The solid-state structures of the ionic liquids are correlated with the solution-state structures through UV-vis spectroscopic studies, further emphasizing the importance of the π interactions in the formation of aggregates. Finally, we investigated the thermal properties of the ionic liquids, revealing complex phase transitions for the iodide-containing species. These phase transitions are further rationalized via the analysis of the data gathered from the structures of the other crystallized salts. 

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 SO 2 F-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 SO 2 F-bearing salts is extended to include active pharmaceutical precursors, allowing for access to functional materials with a priori low toxicity.