Solvation dynamics in a prototypical ionic liquid + dipolar aprotic liquid mixture: 1-butyl-3-methylimidazolium tetrafluoroborate + acetonitrile

Min Liang, Xin Xing Zhang, Anne Kaintz, Nikolaus P. Ernsting, Mark Maroncelli

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Solvation energies, rotation times, and 100 fs to 20 ns solvation response functions of the solute coumarin 153 (C153) in mixtures of 1-butyl-3- methylimidazolium tetrafluoroborate ([Im41][BF4]) + acetonitrile (CH3CN) at room temperature (20.5 C) are reported. Available density, shear viscosity, and electrical conductivity data at 25 C are also collected and parametrized, and new data on refractive indices and component diffusion coefficients presented. Solvation free energies and reorganization energies associated with the S0 â" S 1 transition of C153 are slightly (≤15%) larger in neat [Im 41][BF4] than in CH3CN. No clear evidence for preferential solvation of C153 in these mixtures is found. Composition-dependent diffusion coefficients (D) of Im41+ and CH3CN as well as C153 rotation times (τ) are approximately related to solution viscosity (η) as D, τ ηp with values of p = -0.88, -0.77, and +0.90, respectively. Spectral/solvation response functions (S ν(t)) are bimodal at all compositions, consisting of a subpicosecond fast component followed by a broadly distributed slower component extending over ps-ns times. Integral solvation times (〈τ solv〉 = ∫0∞Sν(t) dt) follow a power law on viscosity for mixture compositions 0.2 ≤ xIL ≤ 1 with p = 0.79. With recent broad-band dielectric measurements [ J. Phys. Chem. B 2012, 116, 7509 ] as input, a simple dielectric continuum model provides predictions for solvation response functions that correctly capture the distinctive bimodal character of the observed response. At xIL ∼ 1 predicted values of 〈τsolv〉 are smaller than those observed by a factor of 2-3, but the two become approximately equal at xIL = 0.2. Predictions of a recent semimolecular theory [ J. Phys. Chem. B 2011, 115, 4011 ] are less accurate, being uniformly slower than the observed solvation dynamics.

Original languageEnglish (US)
Pages (from-to)1340-1352
Number of pages13
JournalJournal of Physical Chemistry B
Volume118
Issue number5
DOIs
StatePublished - Feb 6 2014

Fingerprint

Ionic Liquids
Solvation
Acetonitrile
Ionic liquids
acetonitrile
solvation
Liquids
liquids
viscosity
diffusion coefficient
Chemical analysis
Viscosity
Shear viscosity
1-butyl-3-methylimidazolium tetrafluoroborate
predictions
Free energy
Refractive index
solutes
free energy
refractivity

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

@article{5134837e8bfd49bfbaaabb30c0e8a1da,
title = "Solvation dynamics in a prototypical ionic liquid + dipolar aprotic liquid mixture: 1-butyl-3-methylimidazolium tetrafluoroborate + acetonitrile",
abstract = "Solvation energies, rotation times, and 100 fs to 20 ns solvation response functions of the solute coumarin 153 (C153) in mixtures of 1-butyl-3- methylimidazolium tetrafluoroborate ([Im41][BF4]) + acetonitrile (CH3CN) at room temperature (20.5 C) are reported. Available density, shear viscosity, and electrical conductivity data at 25 C are also collected and parametrized, and new data on refractive indices and component diffusion coefficients presented. Solvation free energies and reorganization energies associated with the S0 {\^a}{"} S 1 transition of C153 are slightly (≤15{\%}) larger in neat [Im 41][BF4] than in CH3CN. No clear evidence for preferential solvation of C153 in these mixtures is found. Composition-dependent diffusion coefficients (D) of Im41+ and CH3CN as well as C153 rotation times (τ) are approximately related to solution viscosity (η) as D, τ ηp with values of p = -0.88, -0.77, and +0.90, respectively. Spectral/solvation response functions (S ν(t)) are bimodal at all compositions, consisting of a subpicosecond fast component followed by a broadly distributed slower component extending over ps-ns times. Integral solvation times (〈τ solv〉 = ∫0∞Sν(t) dt) follow a power law on viscosity for mixture compositions 0.2 ≤ xIL ≤ 1 with p = 0.79. With recent broad-band dielectric measurements [ J. Phys. Chem. B 2012, 116, 7509 ] as input, a simple dielectric continuum model provides predictions for solvation response functions that correctly capture the distinctive bimodal character of the observed response. At xIL ∼ 1 predicted values of 〈τsolv〉 are smaller than those observed by a factor of 2-3, but the two become approximately equal at xIL = 0.2. Predictions of a recent semimolecular theory [ J. Phys. Chem. B 2011, 115, 4011 ] are less accurate, being uniformly slower than the observed solvation dynamics.",
author = "Min Liang and Zhang, {Xin Xing} and Anne Kaintz and Ernsting, {Nikolaus P.} and Mark Maroncelli",
year = "2014",
month = "2",
day = "6",
doi = "10.1021/jp412086t",
language = "English (US)",
volume = "118",
pages = "1340--1352",
journal = "Journal of Physical Chemistry B Materials",
issn = "1520-6106",
publisher = "American Chemical Society",
number = "5",

}

Solvation dynamics in a prototypical ionic liquid + dipolar aprotic liquid mixture : 1-butyl-3-methylimidazolium tetrafluoroborate + acetonitrile. / Liang, Min; Zhang, Xin Xing; Kaintz, Anne; Ernsting, Nikolaus P.; Maroncelli, Mark.

In: Journal of Physical Chemistry B, Vol. 118, No. 5, 06.02.2014, p. 1340-1352.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Solvation dynamics in a prototypical ionic liquid + dipolar aprotic liquid mixture

T2 - 1-butyl-3-methylimidazolium tetrafluoroborate + acetonitrile

AU - Liang, Min

AU - Zhang, Xin Xing

AU - Kaintz, Anne

AU - Ernsting, Nikolaus P.

AU - Maroncelli, Mark

PY - 2014/2/6

Y1 - 2014/2/6

N2 - Solvation energies, rotation times, and 100 fs to 20 ns solvation response functions of the solute coumarin 153 (C153) in mixtures of 1-butyl-3- methylimidazolium tetrafluoroborate ([Im41][BF4]) + acetonitrile (CH3CN) at room temperature (20.5 C) are reported. Available density, shear viscosity, and electrical conductivity data at 25 C are also collected and parametrized, and new data on refractive indices and component diffusion coefficients presented. Solvation free energies and reorganization energies associated with the S0 â" S 1 transition of C153 are slightly (≤15%) larger in neat [Im 41][BF4] than in CH3CN. No clear evidence for preferential solvation of C153 in these mixtures is found. Composition-dependent diffusion coefficients (D) of Im41+ and CH3CN as well as C153 rotation times (τ) are approximately related to solution viscosity (η) as D, τ ηp with values of p = -0.88, -0.77, and +0.90, respectively. Spectral/solvation response functions (S ν(t)) are bimodal at all compositions, consisting of a subpicosecond fast component followed by a broadly distributed slower component extending over ps-ns times. Integral solvation times (〈τ solv〉 = ∫0∞Sν(t) dt) follow a power law on viscosity for mixture compositions 0.2 ≤ xIL ≤ 1 with p = 0.79. With recent broad-band dielectric measurements [ J. Phys. Chem. B 2012, 116, 7509 ] as input, a simple dielectric continuum model provides predictions for solvation response functions that correctly capture the distinctive bimodal character of the observed response. At xIL ∼ 1 predicted values of 〈τsolv〉 are smaller than those observed by a factor of 2-3, but the two become approximately equal at xIL = 0.2. Predictions of a recent semimolecular theory [ J. Phys. Chem. B 2011, 115, 4011 ] are less accurate, being uniformly slower than the observed solvation dynamics.

AB - Solvation energies, rotation times, and 100 fs to 20 ns solvation response functions of the solute coumarin 153 (C153) in mixtures of 1-butyl-3- methylimidazolium tetrafluoroborate ([Im41][BF4]) + acetonitrile (CH3CN) at room temperature (20.5 C) are reported. Available density, shear viscosity, and electrical conductivity data at 25 C are also collected and parametrized, and new data on refractive indices and component diffusion coefficients presented. Solvation free energies and reorganization energies associated with the S0 â" S 1 transition of C153 are slightly (≤15%) larger in neat [Im 41][BF4] than in CH3CN. No clear evidence for preferential solvation of C153 in these mixtures is found. Composition-dependent diffusion coefficients (D) of Im41+ and CH3CN as well as C153 rotation times (τ) are approximately related to solution viscosity (η) as D, τ ηp with values of p = -0.88, -0.77, and +0.90, respectively. Spectral/solvation response functions (S ν(t)) are bimodal at all compositions, consisting of a subpicosecond fast component followed by a broadly distributed slower component extending over ps-ns times. Integral solvation times (〈τ solv〉 = ∫0∞Sν(t) dt) follow a power law on viscosity for mixture compositions 0.2 ≤ xIL ≤ 1 with p = 0.79. With recent broad-band dielectric measurements [ J. Phys. Chem. B 2012, 116, 7509 ] as input, a simple dielectric continuum model provides predictions for solvation response functions that correctly capture the distinctive bimodal character of the observed response. At xIL ∼ 1 predicted values of 〈τsolv〉 are smaller than those observed by a factor of 2-3, but the two become approximately equal at xIL = 0.2. Predictions of a recent semimolecular theory [ J. Phys. Chem. B 2011, 115, 4011 ] are less accurate, being uniformly slower than the observed solvation dynamics.

UR - http://www.scopus.com/inward/record.url?scp=84893864109&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84893864109&partnerID=8YFLogxK

U2 - 10.1021/jp412086t

DO - 10.1021/jp412086t

M3 - Article

C2 - 24422509

AN - SCOPUS:84893864109

VL - 118

SP - 1340

EP - 1352

JO - Journal of Physical Chemistry B Materials

JF - Journal of Physical Chemistry B Materials

SN - 1520-6106

IS - 5

ER -