The potential role of hydrogen bonding in aprotic and protic ionic liquids

Fumino, Koichi; Wulf, Alexander; Ludwig, Ralf

doi:10.1039/b905634c

Cited by 225 publications

(221 citation statements)

References 14 publications

Supporting

Mentioning

203

Contrasting

Unclassified

Order By: Relevance

“…The hydrogen-bonding contribution to the overall interaction energy in aprotic ILs is today widely accepted and well documented among others using far infrared and terahertz spectroscopy (FIR and THZ) studies, [38][39][40] and although such contribution is only about 10 %, the nature of hydrogen-bond interactions (e.g., directional) can significantly influence the properties of such ILs. Generally, ILs can be treated as structured solvents (from ion pairs, ion…”

Section: Ultrasound Absorptionmentioning

confidence: 99%

Ultrasonic Relaxation Study of 1-Alkyl-3-methylimidazolium-Based Room-Temperature Ionic Liquids: Probing the Role of Alkyl Chain Length in the Cation

et al. 2016

View full text Add to dashboard Cite

Ultrasound absorption spectra of four 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide were determined as a function of the alkyl chain length on the cation from 1-propyl-to 1-hexyl-from 293.15 to 323.15 K at ambient pressure. Herein, the ultrasound absorption measurements were carried out using a standard pulse technique within a frequency range from 10 to 300 MHz. Additionally the speed of sound, density and viscosity have been measured. The presence of strong dissipative processes during the ultrasound wave propagation was found experimentally, i.e. relaxation processes in the megahertz range were observed for all compounds over the whole temperature range. The relaxation spectra (both relaxation amplitude and relaxation frequency) were shown to be dependent on the alkyl side chain length of the 1-alkyl-3-methylimidazolium ring. In most cases, a single Debye model described the absorption spectra very well. However, a comparison of the determined spectra with the spectra of a few other imidazolium-based ionic liquids reported in the literature (in part recalculated in this work) shows that the complexity of the spectra increases rapidly with the elongation of the alkyl chain length on the cation.This complexity indicates that both the volume viscosity and the shear viscosity are involved in relaxation processes even in relatively low frequency ranges. As a consequence, the sound velocity dispersion is present at relatively low megahertz frequencies.

show abstract

Section: Ultrasound Absorptionmentioning

confidence: 99%

Ultrasonic Relaxation Study of 1-Alkyl-3-methylimidazolium-Based Room-Temperature Ionic Liquids: Probing the Role of Alkyl Chain Length in the Cation

et al. 2016

View full text Add to dashboard Cite

show abstract

“…A well-known example is the acid hydrogen at carbon C-2 of the imidazolium ring. 20,55 Protic ILs result from proton transfer in stoichiometric mixtures of a Brønsted acid with a Brønsted base B 56 3 ] is highly hydrophilic and forms a H-bonded network, which in some regards resembles the H-bonded network of water. 58,59 The propensity to form H-bonds can also be designed into cations by functionalization of side chains.…”

Section: Bis(trifluoromethanesulfonyl)imidementioning

confidence: 99%

How ionic liquids can help to stabilize native proteins

Weingärtner

Cabrele

Herrmann

2012

Phys. Chem. Chem. Phys.

258

233

View full text Add to dashboard Cite

The native state of a globular protein is essential for its biocatalytic function, but is marginally stable against unfolding. While unfolding equilibria are often reversible, folding intermediates and misfolds can promote irreversible protein aggregation into amorphous precipitates or highly ordered amyloid states. Addition of ionic liquids-low-melting organic salts-offers intriguing prospects for stabilizing native proteins and their enzymatic function against these deactivating reaction channels. The huge number of cations and anions that form ionic liquids allows fine-tuning of their solvent properties, which offers robust and efficient strategies for solvent optimization. Going beyond case-by-case studies, this article aims at discussing principles for a rational design of ionic liquid-based formulations in protein chemistry and biocatalysis.

show abstract

“…Ab-initio-Methoden lassen auf einen engen Zusammmenhang zwischen den berechneten Wechselwirkungsenergien von IL-Aggregaten und den gemessenen intermolekularen Streckschwingungsfrequenzen schließen. [24] Beide Eigenschaften gehen einher mit wachsenden Mög [28] Wir demonstrieren nun, dass Wasserstoffbrücken wesentliche Bedeutung haben und selbst kleine lokale Wechselwirkungen zu charakteristisch verschiedenen Festkörperstrukturen von I und III führen.…”

unclassified