Analyzing the interaction energies between cation and anion in ionic liquids: The subtle balance between Coulomb forces and hydrogen bonding

Controlling the subtle energy balance in protic ionic liquids: dispersion forces compete with hydrogen bonds

The properties of ionic liquids are determined by the energy-balance between Coulomb-interaction, hydrogen-bonding, and dispersion forces. Out of a set of protic ionic liquids (PILs), including trialkylammonium cations and methylsulfonate and triflate anions we could detect the transfer from hydrogen-bonding to dispersion-dominated interaction between cation and anion in the PIL [(C6 H13 )3 NH][CF3 SO3 ]. The characteristic vibrational features for both ion-pair species can be detected and assigned in the far-infrared spectra. Our approach gives direct access to the relative strength of hydrogen-bonding and dispersion forces in a Coulomb-dominated system. Dispersion-corrected density functional theory (DFT) calculations support the experimental findings. The dispersion forces could be quantified to contribute about 2.3 kJ mol(-1) per additional methylene group in the alkyl chains of the ammonium cation.

Hydrogen bonding in a mixture of protic ionic liquids: a molecular dynamics simulation study

We report results of molecular dynamics (MD) simulations characterising the hydrogen bonding in mixtures of two different protic ionic liquids sharing the same cation: triethylammonium-methylsulfonate (TEAMS) and triethylammonium-triflate (TEATF).

Computational approaches to understanding reaction outcomes of organic processes in ionic liquids

The utility of using a combined experimental and computational approach for understanding ionic liquid media, and their effect on reaction outcome, is highlighted through a number of case studies.

1-Ethyl-2,3-dimethylimidazolium paramagnetic ionic liquids with 3D magnetic ordering in its solid state: synthesis, structure and magneto-structural correlations

We present two novel paramagnetic ionic liquids, Edimim FeX₄ (X = Cl and Br), which display a three-dimensional magnetic ordering below 10 K. Exhaustive and systematic studies of the magneto-structural correlations have been performed.

Spectroscopic evidence of ‘jumping and pecking’ of cholinium and H-bond enhanced cation–cation interaction in ionic liquids

Spectroscopic evidence for cation–cation interaction in ionic liquids. The repulsive electrostatic interaction is overcome by hydrogen bonding between ions of like charge.

Observation of aliphatic C–H⋯X hydrogen bonds in imidazolium ionic liquids

Measurement of H/D isotope effects on the¹⁹F resonances of sequentially deuterated 1-n-butyl-3-methylimidazolium hexafluorophosphate and tetrafluoroborate isotopologues reveals the formation of aliphatic C–H⋯X hydrogen bonds between the fluorinated anions and protons along theN-alkyl sidechains of the cations.

Probing molecular interaction in ionic liquids by low frequency spectroscopy: Coulomb energy, hydrogen bonding and dispersion forces

Low vibrational spectroscopy provides detailed information on the strength and type of interaction and their influence on the properties of ionic liquids.