Spectroscopic and Computational Insight into the Intermolecular Interactions between Zwitter‐Type Ionic Liquids and Water Molecules

Abstract

Geometric and conformational changes of zwitter-type ionic liquids (ZILs) due to hydrogen-bonding interactions with water molecules are investigated by density functional theory (DFT), two-dimensional IR correlation spectroscopy (2D IR COS), and pulsed-gradient spin-echo NMR (PGSE NMR). Simulation results indicate that molecular structures in the optimized states are strongly influenced by hydrogen bonding of water molecules with the sulfonate group or imidazolium and pyrrolidinium rings of 3-(1-methyl-3-imidazolio)propanesulfonate (1) and 3-(1-methyl-1-pyrrolidinio)propanesulfonate (2), respectively. Concentration-dependent 2D IR COS reveals kinetic conformational changes of the two ZIL-H(2)O systems attributable to intermolecular interactions, as well as the interactions of sulfonate groups and imidazolium or pyrrolidinium rings with water molecules. The dramatic changes in the (1)H self-diffusion coefficients elucidate the formation of proton-conduction pathways consisting of ZIL networks. In ZIL domains, protons are transferred by a Grotthuss-type mechanism through formation, breaking, and restructuring of bonds between ZILs and H(2)O, leading to an energetically favorable state. The simulation and experimental investigations delineated herein provide a perspective to understanding the interactions with water from an academic point of view as well as to designing ILs with desired properties from the viewpoint of applications.

Lithium-Containing Zwitterionic Poly(Ionic Liquid)s as Polymer Electrolytes for Lithium-Ion Batteries

“…The IR spectra of powder monomeric VIPS, polymeric film poly­([VIPS]­[LiTFSI]) without PC, and gel electrolyte film containing 50 wt % PC (PIL/50PC) were recorded at room temperature and are shown in Figure . The original zwitterion VIPS shows two absorption bands at 1033 and 1179 cm –1 , which can be assigned to the SO stretching vibrations of the sulfate group. , After the addition of equimolecular LiTFSI, these absorption bands of the obtained PIL exhibit prominent blue shifts to 1053 and 1183 cm –1 , respectively. Futher addition of 50 wt % PC leads to higher wavenumber shifts to 1057 and 1185 cm –1 , respectively.…”

“…The original zwitterion VIPS shows two absorption bands at 1033 and 1179 cm −1 , which can be assigned to the SO stretching vibrations of the sulfate group. 41,42 After the addition of equimolecular LiTFSI, these absorption bands of the obtained PIL exhibit prominent blue shifts to 1053 and 1183 cm −1 , respectively. Futher addition of 50 wt % PC leads to higher wavenumber shifts to 1057 and 1185 cm −1 , respectively.…”

Lean-water hydrogel electrolyte for zinc ion batteries

“…2c ). The two absorption peaks at 1033 and 1179 cm −1 were attributed to the stretching vibration of S = O in the sulfate groups 32 , 33 . When Zn 2+ is introduced, both peaks blueshift to 1038 and 1181 cm −1 , evidencing the intermolecular electrostatic interactions between Zn 2+ and SO 3 − .…”

Data on synthesis and characterization of sulfonated poly(phenylnorbornene) and polymer electrolyte membranes based on it

“…1-Ethyl-3-methylimidazolium tetrafluoroborate (IL) was synthesized by literature procedure [19]. Zwitter-type ion liquid 3-(1-methyl-3-imidazolio)propanesulfonate (ZI) was synthesized by literature procedure [20].…”