Sum Frequency Generation Studies of Ammonium and Pyrrolidinium Ionic Liquids Based on the Bis-trifluoromethanesulfonimide Anion

Aliaga, César; Baker, Gary A.; Baldelli, Steven

doi:10.1021/jp077008g

Cited by 44 publications

(55 citation statements)

References 61 publications

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“…The presence of a bulky, voluminous anion strongly distorts the ordering in the IL caused by the presence of an explicit interface. The side chains of the cations form, on average, an angle between 25 and 40°with the normal to the interface, in good agreement with the observations of Aliaga et al71 using sum frequency generation experiments. The analysis of the preferential orientation of the different anions shows several remarkable features.…”

supporting

confidence: 89%

Bulk and Liquid–Vapor Interface of Pyrrolidinium-Based Ionic Liquids: A Molecular Simulation Study

et al. 2014

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Using molecular dynamics simulations, we have studied the structure of three 1-butyl-1-methylpyrrolidinium ionic liquids whose anions are triflate, bis(trifluoromethanesulfonyl)imide, and tris(pentafluoroethyl)trifluorophosphate. The structure of the bulk phase of the three ionic liquids has been interpreted using radial and spatial distribution functions and structure factors that allows us to characterize the morphology of the polar and nonpolar domains present in this family of liquids. The size of the polar regions depends on the anion size, whereas the morphology of the nonpolar domains is anion-independent. Furthermore, the surface ordering properties of the ionic liquids and charge and density profiles were also studied using molecular simulations. The surface tension of the liquid-vapor interfaces of these ionic liquids was also predicted from our molecular simulations. In addition, microscopic structural analysis of orientational ordering at the interface and density profiles along the direction normal to the interface suggest that the alkyl chains of the cation tend to protrude toward the vacuum, and the presence of the interface leads to a strong organization of the liquid phase in the region close to the interface. In the interfacial area, the polar regions of the ionic liquids are more structured than those in the bulk phase, whereas the opposite behavior is observed for the nonpolar regions.

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supporting

confidence: 89%

Bulk and Liquid–Vapor Interface of Pyrrolidinium-Based Ionic Liquids: A Molecular Simulation Study

et al. 2014

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“…These features can be attributed to the low lattice energy of [Tf 2 N À ] salts because of the highly delocalized anionic structure, as detailed by a number of groups. [16][17][18] The expected structures of these RTILs were confirmed using 1 H/ 13 C NMR and FTIR spectroscopy. The results of the characterization of the RTILs and the details of the QENS experiment are reported in the Experimental Section.…”

Section: Resultsmentioning

confidence: 74%

Microscopic Diffusion Dynamics of Silver Complex‐Based Room‐Temperature Ionic Liquids Probed by Quasielastic Neutron Scattering

Mamontov¹,

Baker²,

Luo³

et al. 2011

ChemPhysChem

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Quasielastic neutron scattering is used to probe the microscopic diffusion dynamics of the hydrogen-bearing cations of two different silver complex-derived room-temperature ionic liquids, [Ag(propylamine)(2)(+)][Tf(2)N(-)] (Tf=trifluoromethanesulfonyl) and [Ag(1-pentene)(+)][Tf(2)N(-)]. In the temperature range from 300 to 340 K, analysis of the scattering momentum transfer dependence of the data provides evidence for three distinct diffusion components. The slowest component describes the long-range cationic translational diffusion. A possible link between the microscopic diffusion parameters and the structural features of the cations comprising these two ionic liquids is discussed.

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“…As observed in Figure 8a, the terminal carbon atoms (C9) of the propyl groups of [PPy][Tfo] seem to locate in the outmost position of the interfacial region, successively followed by C8 atoms and C7 atoms, which is in good agreement with the simulation and experimental results in the previous report that the alkyl chain was inclined to be perpendicular to the surface and pointing into the vacuum. 59,60 As for the distribution of the anion [Tfo] − , represented by the C3 and S2 atoms of the anion, tends to be aligned with the surface normal and the anionic CF 3 groups are exposed at the surface. However, as shown in Figure 8b, when adding sulfonic acid groups into the terminal methyl group of the propyl group, the ordering preference of the alkyl tails of the [PSPy] + cation is almost the opposite of that observed in [PPy] + , with the order of C7atoms, C8 atoms, C9 atoms, and S1 atoms from the vacuum side into the bulk liquid.…”

Section: Ndps Of Three Ils ([Ppy][tfo] [Pspy][tfo] and [Hspy]-mentioning

confidence: 99%

Proton Microenvironment and Interfacial Structure of Sulfonic-Acid-Functionalized Ionic Liquids

Shan

Yang

et al. 2015

J. Phys. Chem. C

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Sulfonic-acid-functionalized ionic liquids (SFILs) have shown promising performance in catalytic reactions and development of new proton conductive materials. In this work, molecular dynamic simulation based on the ion pair charge approach has been performed to investigate the structural characteristic of several typical SFILs in both bulk liquids and the vacuum−liquid interfacial region. The results showed that anions play a critical role in determining the microenvironment of the terminal sulfonic acid proton in SFILs, and less basic anions lead to a much weaker association of sulfonic acid protons with anions. A significant aggregation of sulfonic acid side chains existed in SFILs because of the strong interaction between different sulfonic acid groups. A sharp change in the ordering preference of alkyl tails and pyridine rings at vacuum−liquid interfaces was observed after the introduction of a sulfonic acid group to the side chain of the cation of ionic liquids, and the properties of the anions have a remarkable influence on the preferential location of anions in the interfacial region. These results can aid in understanding of the physiochemical properties of SFILs and thus facilitate the development of new SFILs and proton conductive materials.

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Sum Frequency Generation Studies of Ammonium and Pyrrolidinium Ionic Liquids Based on the Bis-trifluoromethanesulfonimide Anion

Cited by 44 publications

References 61 publications

Bulk and Liquid–Vapor Interface of Pyrrolidinium-Based Ionic Liquids: A Molecular Simulation Study

Bulk and Liquid–Vapor Interface of Pyrrolidinium-Based Ionic Liquids: A Molecular Simulation Study

Microscopic Diffusion Dynamics of Silver Complex‐Based Room‐Temperature Ionic Liquids Probed by Quasielastic Neutron Scattering

Proton Microenvironment and Interfacial Structure of Sulfonic-Acid-Functionalized Ionic Liquids

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