Nanostructure domains, voids, and low-frequency spectra in binary mixtures of <i>N</i>,<i>N</i>-dimethylacetamide and ionic liquids with varying cationic size

Reddy, Th. Dhileep N.; Mallik, Bhabani S.

doi:10.1039/c9ra09041j

Cited by 9 publications

(3 citation statements)

References 94 publications

(112 reference statements)

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“…Therefore, the Voronoi method enables us to determine the domain count, i.e., compute the number of domains formed by each group in a system throughout the trajectory length scale. Further, details of the domain analysis method are presented in the previous papers. − In this study, we use TRAVIS , software and calculate the number of domains formed by each group, volume occupied by the domains, surface coverage, and the isoperimetric quotient Q peri defined as follows In the above equation, r sphere ( V ) and r sphere ( A ) represent the radii calculated from the volume and area, respectively. Both the volume and the area are determined from the Voronoi tessellation method.…”

Section: Resultsmentioning

confidence: 99%

Microheterogeneity-Induced Vibrational Spectral Dynamics of Aqueous 1-Alkyl-3-methylimidazolium Tetrafluoroborate Ionic Liquids of Different Cationic Chain Lengths

Biswas

Mallik

2022

J. Phys. Chem. B

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We have monitored the impacts of an increment in the alkyl chain length of the imidazolium-based tetrafluoroborate ionic liquids on the local deuteroxyl probe modes of interest. For this study, we have taken 1-ethyl-3-methylimidazolium tetrafluoroborate [EMIm][BF4], 1-butyl-3-methylimidazolium tetrafluoroborate [BMIm][BF4], 1-octyl-3-methylimidazolium tetrafluoroborate [OMIm][BF4], and 1-decyl-3-methylimidazolium tetrafluoroborate [DMIm][BF4] ionic liquid solutions with 5% HOD in H2O as the vibrational reporter of the associated ultrafast system dynamics. Classical molecular dynamics (MD) simulations were employed to determine molecular structure and dynamic properties, while the spectral profiles were derived by applying the wavelet analysis of classical trajectories. Spatial distribution functions reveal the heterogeneity within the molecular structures of the ionic liquids (ILs) with varying alkyl chain lengths. The intense position of the spectral peak, the frequency corresponding to the shoulder peak, and the spectral linewidth of the O–D stretch distribution are not influenced by the increment in the cationic chain length. In addition, the ionic liquid (IL) [BMIm][BF4] exhibits a notable trend; the dynamic timescales are longer than the other studied systems. Therefore, we have performed the Voronoi decomposition analysis of the ionic and the polar–apolar domains, symmetrically increasing the length of alkyl chains on the IL cations. Domain analysis reveals structural microheterogeneity; the anions form discrete domains, and the ionic liquid constituting cations form continuous domains irrespective of the alkyl chain length on the imidazolium cations. Therefore, this computational ultrafast spectroscopy study aids in forming a molecular-level picture of the ionic liquid cations and anions in the liquid phase, providing a detailed interpretation of the spectral properties of the probe stretching vibrations.

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Section: Resultsmentioning

confidence: 99%

Microheterogeneity-Induced Vibrational Spectral Dynamics of Aqueous 1-Alkyl-3-methylimidazolium Tetrafluoroborate Ionic Liquids of Different Cationic Chain Lengths

Biswas

Mallik

2022

J. Phys. Chem. B

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“…The interstitial sphere connects to the Delaunay simplex. , The tessellation method used in the present study is based on the construction of Delaunay simplexes on the surface of the four closest atoms. This method is called weighted or Voronoi tessellation. ,− The Voronoi tessellation method used in this analysis differs from the classical approach, where only the center of the atoms was considered. , A tangent to the surface of the atoms is drawn, and the distance is calculated from the tangent . The diameters of the atoms that are considered from the Lennard-Jones parameters (σ) are used to calculate the voids.…”

Section: Resultsmentioning

confidence: 99%

Hydrogen Bond Kinetics, Ionic Dynamics, and Voids in the Binary Mixtures of Protic Ionic Liquids with Alkanolamines

Reddy

Mallik

2021

J. Phys. Chem. B

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Classical molecular dynamics simulations were used to investigate the structural and dynamical properties of the mixtures of ionic liquids (ILs) with the conjugate forms of the cation in a 1:1 molar ratio. The experimental studies suggested the combination of ethanolamines and ILs as novel absorbents for acidic gases such as CO2 and H2S, which provide the advantage of efficient absorption of gases at low pressures. However, the microscopic properties of the ionic mixtures are not studied. From our computational investigations, the densities of mixtures are reported and compared with the experimental results. The structural evolution of mixtures is reported by radial distribution functions, coordination numbers, void analysis, and spatial distribution functions. The mixtures’ dynamic properties were studied by analyzing the hydrogen bond, ion-pair, and ion-cage lifetimes of the system. Monoethanolammonium and triethanolammonium ILs show different types of spatial distribution functions. The cations have lesser effect on dynamics compared with anions. The charge on the anion greatly affects the dynamics of mixtures. The dianion mixtures show slower dynamics than the monoanionic mixtures. The hydrogen bonding between cations and anions is stronger than that between cations and neutral molecules due to strong coulombic attractive forces. The cations spend more time around the dianions as compared to monoanions. The distributions of voids show that the void sizes are smaller in triethanolamine-based mixtures. The sulfobenzoate-based mixtures show voids smaller than those of pyridine-3-carboxylate-based mixtures due to more available free space between the entities, which facilitates the overall dynamics.

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“…19,20 Three-dimensional spatial distribution functions (SDF) and combined distribution functions (CDF) combining radial and angle distribution can be computed for a more detailed analysis of pairwise interactions. 21,22 A heterogeneity order parameter (HOP) has been used in a number of works. [23][24][25][26] This parameter is the average of the Gaussian exponential function of the interatomic distances between certain types of atoms and has high values when many close contacts between such atoms exist.…”

Section: Introductionmentioning

confidence: 99%

Highlighting the difference in nanostructure between domain-forming and domainless protic ionic liquids

Sedov

Magsumov

2022

Phys. Chem. Chem. Phys.

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Nanostructure domains, voids, and low-frequency spectra in binary mixtures of N,N-dimethylacetamide and ionic liquids with varying cationic size

Abstract: Classical MD simulations were carried out on binary mixtures of DMA with hydroxide based ammonium ILs, TEAH, TPAH and TBAH, at three different mole fractions of IL.

Cited by 9 publications

References 94 publications

Microheterogeneity-Induced Vibrational Spectral Dynamics of Aqueous 1-Alkyl-3-methylimidazolium Tetrafluoroborate Ionic Liquids of Different Cationic Chain Lengths

Microheterogeneity-Induced Vibrational Spectral Dynamics of Aqueous 1-Alkyl-3-methylimidazolium Tetrafluoroborate Ionic Liquids of Different Cationic Chain Lengths

Hydrogen Bond Kinetics, Ionic Dynamics, and Voids in the Binary Mixtures of Protic Ionic Liquids with Alkanolamines

Highlighting the difference in nanostructure between domain-forming and domainless protic ionic liquids

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