Pressure-Induced Spectral Changes of Room-Temperature Ionic Liquid, N,N-Diethyl-N-methyl-N-(2-methoxyethyl)ammonium Bis(trifluoromethylsulfonyl)imide, [DEME][TFSI]

Yoshimura, Yukihiro; Takekiyo, Takahiro; Imai, Yusuke; Abe, Hiroshi

doi:10.1021/jp205314f

Cited by 55 publications

(73 citation statements)

References 28 publications

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“…In contrast, no crystallization of [C 4 C 1 Im]BF 4 has been observed even at 30.0 GPa . Interestingly, in case of ionic liquids based on the N,N‐diethyl‐N‐methyl‐N‐(2‐methoxyehtyl)ammonium cation, crystallization was observed at 1.2 GPa for the case of BF 4 ‐ anion, whereas crystallization was not observed for the case of [Tf 2 N] ‐ anion even at 5.5 GPa . In fact, we have observed an interesting contrast between the behavior under high pressure of a [Tf 2 N] ‐ ‐based ionic liquid and another ionic liquid with a simple anion, while keeping the same cation: no crystallization was observed for [C 6 C 1 Im][Tf 2 N] up to 4.3 GPa, whereas crystallization of [C 6 C 1 Im]Br was observed already at 1.4 GPa (data not shown).…”

Section: Resultsmentioning

confidence: 59%

Ionic liquids based on the bis(trifluoromethylsulfonyl)imide anion for high‐pressure Raman spectroscopy measurements

Faria

Nobrega

Temperini

et al. 2012

J Raman Spectroscopy

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Assembling a diamond anvil cell for high‐pressure measurements involves placing in a gasket hole the sample of interest, a pressure transmitting fluid, and a material for pressure calibration. In this communication, we propose the use of ionic liquids containing the bis(trifluoromethylsulfonyl)imide anion ([Tf2N]‐), [(CF3SO2)2 N]‐, as a simultaneous pressure transmitting and calibrant material for high‐pressure Raman spectroscopy measurements of solid samples that are not soluble in ionic liquids. The position of the characteristic Raman band of the [Tf2N]‐ anion at 740 cm−1 exhibits linear frequency shift for pressures up to 2.5 GPa. High‐pressure Raman spectra of different ionic liquids containing the same anion indicate that the actual magnitude of the pressure‐induced frequency shift of the [Tf2N]‐ normal mode depends on the counterion, the typical shift being 4.2 cm−1/GPa. Ionic liquids based on the [Tf2N]‐ anion are also good pressure transmitting mediums because hydrostatic condition is kept at high pressure, and no crystallization is observed up to 4.0 GPa. Copyright © 2012 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 59%

Ionic liquids based on the bis(trifluoromethylsulfonyl)imide anion for high‐pressure Raman spectroscopy measurements

Faria

Nobrega

Temperini

et al. 2012

J Raman Spectroscopy

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“…(In crystals, typically only one conformer is present although there can be exceptions.) This equilibrium has been studied experimentally by Raman spectroscopy 20,43 and by electronic structure and molecular dynamics (MD) simulations. 12,43–48 Under ambient conditions the trans conformer is slightly favored 20,43 and the enthalpy change from the trans conformer to cis is positive by about 3.5 kJ/mol according to temperature-dependent Raman spectroscopy 43 and supported by MD simulations.…”

Section: Resultsmentioning

confidence: 99%

“…This equilibrium has been studied experimentally by Raman spectroscopy 20,43 and by electronic structure and molecular dynamics (MD) simulations. 12,43–48 Under ambient conditions the trans conformer is slightly favored 20,43 and the enthalpy change from the trans conformer to cis is positive by about 3.5 kJ/mol according to temperature-dependent Raman spectroscopy 43 and supported by MD simulations. 12 Pressure-dependent Raman spectroscopy 20 on N,N -diethyl- N -methyl- N -(2-methoxyethyl)ammonium (DEME) TFSA showed an increasing trans / cis ratio with increasing pressure, finding that the partial molar volume of the trans -TFSA anion conformer is 0.7 cm 3 /mol smaller than that of the cis one for that system.…”

Section: Resultsmentioning

confidence: 99%

Do TFSA Anions Slither? Pressure Exposes the Role of TFSA Conformational Exchange in Self-Diffusion

et al. 2015

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Multi-nuclear (1H, 2H, and 19F) magnetic resonance spectroscopy techniques as functions of temperature and pressure were applied to the study of selectively deuterated 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (EMIM TFSA) ionic liquid isotopologues and related ionic liquids. For EMIM TFSA, temperature-dependent 2H T1 data indicate stronger electric field gradients in the alkyl chain region compared to the imidazolium ring. Most significantly, the pressure dependences of the EMIM and TFSA self-diffusion coefficients revealed that the displacements of the cations and anions are independent, with diffusion of the TFSA anions being slowed much more by increasing pressure than for the EMIM cations, as shown by their respective activation volumes (28.8 ± 2.5 cm3/mol for TFSA vs. 14.6 ± 1.3 cm3/mol for EMIM). Increasing pressure may lower the mobility of the TFSA anion by hindering its interconversion between trans and cis conformers, a process that is coupled to diffusion according to published molecular dynamics simulations. Measured activation volumes (ΔV‡) for ion self-diffusion in EMIM bis(fluoromethylsulfonyl)amide and EMIM tetrafluoroborate support this hypothesis. In addition, 2H T1 data suggests increased ordering with increasing pressure, with two T1 regimes observed for the MD3 and D2 isotopologues between 0.1–100 and 100–250 MPa respectively. The activation volumes for T1 were 21 and 25 (0–100 MPa) and 11 and 12 (100–250 MPa) cm3/mol for the MD3 and D2 isotopologues, respectively.

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“…Indeed, a pressure‐induced liquid–solid transition (thus, a transition to a less hydrostatic environment) can be clearly detected by the abrupt increase of this linewidth Γ( p ), as a consequence of the occurrence of nonhydrostatic stresses . This method has been exploited to determine the solidification transition of glass‐formers and, more recently, of ILs . Γ( p ) is obtained at each working pressure by fitting the ruby fluorescence signal by two Lorentzian functions.…”

Section: Resultsmentioning

confidence: 99%

“…The liquid–solid transition can be obtained by cooling or by volume compression. They are not equivalent thermodynamic processes because applying pressure mainly induces a variation of density, whereas temperature varies simultaneously kinetic energy and density . In addiction, applying pressure allows the system to experience the repulsive part of the intermolecular potential.…”

Section: Introductionmentioning

confidence: 99%

Pressurizing the mixtures of two ionic liquids: Crystallization versus vetrification

Capitani

Trequattrini

Palumbo³

et al. 2017

J Raman Spectroscopy

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A series of mixtures prepared with different content of the ionic liquids N‐trimethyl‐N‐propylammonium bis(trifluoromethylsulfonyl)imide (TMPA‐TFSI) and N‐trimethyl‐N‐hexylammonium bis(trifluoromethylsulfonyl)imide (TMHA‐TFSI), namely, (TMPA‐TFSI)100−x (TMHA‐TFSI)x, is investigated by means of Raman spectroscopy as a function of pressure at room temperature. Both pure TMPA‐TFSI and the x = 2 mixture crystallize under an applied pressure lower than 1 GPa. On the contrary, for x > 7, none of the investigated mixtures crystallize, but they undergo a glass transition over the 1–2 GPa pressure range. We suggest that the disorder induced by the high number of possible configurations for the longer alkyl chain of TMHA‐TFSI in a compressed environment is a key factor in the suppression of the crystallization process.

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Pressure-Induced Spectral Changes of Room-Temperature Ionic Liquid, N,N-Diethyl-N-methyl-N-(2-methoxyethyl)ammonium Bis(trifluoromethylsulfonyl)imide, [DEME][TFSI]

Cited by 55 publications

References 28 publications

Ionic liquids based on the bis(trifluoromethylsulfonyl)imide anion for high‐pressure Raman spectroscopy measurements

Ionic liquids based on the bis(trifluoromethylsulfonyl)imide anion for high‐pressure Raman spectroscopy measurements

Do TFSA Anions Slither? Pressure Exposes the Role of TFSA Conformational Exchange in Self-Diffusion

Pressurizing the mixtures of two ionic liquids: Crystallization versus vetrification

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