Structures of Ionic Liquids with Different Anions Studied by Infrared Vibration Spectroscopy

Jeon, Young-Deuk; Sung, Jaeho; Seo, Choongwon; Lim, Hyunji; Cheong, Hyeonsik; Kang, Minhyuck; Moon, Bongjin; Ouchi, Yukio; Kim, Doseok

doi:10.1021/jp7120752

Cited by 269 publications

(309 citation statements)

References 40 publications

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“…71−81 Spectral bands in the region from 3200 to 3000 cm −1 are attributed to the coupled aromatic ring C−H stretching vibrations of the imidazolium hydrogen atoms, while those between 3000 and 2850 cm −1 can be assigned to the aliphatic C−H stretches of the CH 2 and CH 3 groups of the ethyl chain and of the CH 3 group bonded directly to the [C 2 MIM + ] ring. [71][72][73][74][75][76][77][78]81 4 ] thin films to water vapor in the sealed ATR cell at different levels of RH at 295 K. After each RH adjustment, spectra were collected until the band intensities stopped changing to ensure that equilibrium was attained. It typically took ∼20 min for the system to equilibrate.…”

Section: ■ Introductionmentioning

confidence: 99%

“…At low RH, there are two well-resolved bands, which can be assigned as the ν 3 asymmetric stretch at 3640 cm −1 and the ν 1 symmetric stretch at 3562 cm −1 of a water molecule that is H-bonded to two [BF 4 − ] anions, as suggested previously. 19,27,30,81,83 As the RH is increased to ∼90% RH, the intensities of the ν 3 and ν 1 O−H stretches increase and the positions shift to ∼3625 and ∼3568 cm −1 , respectively. A "liquid-like" water peak at 3454 cm −1 and a shoulder at 3270 cm −1 also appear and grow, indicative of Equilibrium Molar Fraction of Water in ILs.…”

Section: ■ Introductionmentioning

confidence: 99%

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Interaction of Water Vapor with the Surfaces of Imidazolium-Based Ionic Liquid Nanoparticles and Thin Films

et al. 2012

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Understanding the interactions of humid air with ionic liquids (ILs) is critical for predicting how their physicochemical properties are affected by water. Using experimental and theoretical techniques, water vapor's interaction with aerosolized nanoparticles and thin films of [C 2 MIM][Cl] and [C 2 MIM][BF 4 ] was studied. Solutions were electrosprayed to produce dry particles. Particles' hygroscopic growth was quantified using tandem nanodifferential mobility analysis as a function of relative humidity (RH). This is the first report of the interaction of water with aerosolized IL nanoparticles. The particles' small size allows true IL−water vapor equilibrium achieved quickly. Growth curves for both ILs show steady water uptake with increasing RH. Water vapor uptake by IL thin films was also examined using ATR-FTIR spectroscopy. . They represent a large class of molecules that have unique and widely tunable physical and chemical properties. 1−3 For example, there is a significant interest in the use of ILs in green chemistry, 2,4,5 due to their negligible vapor pressure at room temperature, 6 and for many other applications including solvents in synthesis and catalysis, 1,6 chemical extraction, 1,2,5 and fuel cells. 7 Physical properties such as conductivity, viscosity, density, and surface tension of ILs are known to depend on the presence of water, both adsorbed and absorbed. 3,8 Water is ubiquitous in the environment, and hygroscopic ILs such as those with imidazolium-based cations can uptake significant amounts of water vapor from ambient air, which alters their physical and chemical properties. 1,3 Thus, quantification of water uptake by hygroscopic ILs and understanding how the presence of water affects the nature of the ion−ion and ion−water interactions are critical for use of ILs in future applications. 8−14 Numerous experimental and theoretical studies have investigated the interaction of imidazolium-based ILs with water. 3,8−35 It is understood that both the cation and the anion have an effect on how ILs interact with water, with the anion having a stronger effect. 3,17,19 Early experimental work by Seddon et al. investigated the miscibility of water with ILs containing 1-nalkyl-3-methylimidazolium ([C n MIM + ], n = number of carbons on the linear alkyl chain) cations and various anions at room temperature. 3 It was determined that, regardless of the alkyl chain length, all halide anions were fully soluble in water and all hexafluorophosphate ([PF 6 − ]) anions were insoluble. 3 However, alkyl chain length did have an effect on water miscibility of [C n MIM + ]-based ILs with tetrafluoroborate ([BF 4 − ]) anions; for chain lengths of n = 2 or 4, the ILs were fully miscible, but for n > 4, the ILs formed biphasic systems. 3 Cammarata et al. performed early attenuated total reflection (ATR) infrared (IR) studies on the molecular states of water

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Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Interaction of Water Vapor with the Surfaces of Imidazolium-Based Ionic Liquid Nanoparticles and Thin Films

et al. 2012

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“…In comparison to the IR spectra of pure [BMIM][BF 4 ] (Fig. 5b), the presence of 4 ] between 2800 to 3000 cm À1 , originated from the butyl chain attached to the imidazolium ring, and at 3122 and 3163 cm À1 , attributed to the antisymmetric and symmetric C-H vibrational mode of the imidazolium ring, [27] all suggest a [BMIM] [BF 4 ] layer is adsorbed onto the surface of the hybrid materials. As the sample has already been washed repetitively with acetonitrile and ethanol before the spectroscopic measurements, it is concluded that this adsorption is relatively strong.…”

Section: Resultsmentioning

confidence: 93%

Decorating Semiconductor Silver-Tetracyanoquinodimethane Nanowires with Silver Nanoparticles from Ionic Liquids

et al. 2014

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Hybrid semiconducting silver-tetracyanoquinodimethane (AgTCNQ) nanowires decorated with Ag nanoparticles have been synthesized at room temperature in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate. Hydroquinone was applied to reduce Ag þ and TCNQ to silver nanoparticles, and TCNQ À , respectively, under ambient conditions. AgTCNQ nanowires were formed via spontaneous electrolysis between Ag metal nanoparticles and TCNQ, and reaction between Ag þ and TCNQ À . Microscopic, spectroscopic, and X-ray characterizations all confirmed the formation of crystalline Ag nanoparticle-AgTCNQ nanowire hybrid structures. The ionic liquid was used as a reaction medium, but also as a stabilizing (or blocking) agent to control the nucleation and growth rate of AgTCNQ wires.

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“…Further reduction in droplet volume can be achieved by decreasing the size of microstructures and/or using spin coating to achieve thinner IL droplets ( Supplementary Fig. 2d 20 . These liquid-stable IL microdroplets may find applications in understanding the fundamental properties of micro-scale interfaces between immiscible liquids, as well as a range of applications at liquid-liquid interfaces such as electrochemical sensors, solvent extraction, pharmacokinetics and solar energy conversion 21 .…”

Section: Article Nature Communications | Doi: 101038/ncomms4744mentioning

confidence: 99%

Robust and versatile ionic liquid microarrays achieved by microcontact printing

Gunawan

Zhao

2014

Nat Commun

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Lab-on-a-chip and miniaturized systems have gained significant popularity motivated by marked differences in material performance at the micro-to-nano-scale realm. However, to fully exploit micro-to-nano-scale chemistry, solvent volatility and lack of reproducibility need to be overcome. Here, we combine the non-volatile and versatile nature of ionic liquids with microcontact printing in an attempt to establish a facile protocol for high throughput fabrication of open microreactors and microfluidics. The micropatterned ionic liquid droplets have been demonstrated as electrochemical cells and reactors for microfabrication of metals and charge transfer complexes, substrates for immobilization of proteins and as membrane-free high-performance amperometric gas sensor arrays. The results suggest that miniaturized ionic liquid systems can be used to solve the problems of solvent volatility and slow mass transport in viscous ionic liquids in lab-on-a-chip devices, thus providing a versatile platform for a diverse number of applications.

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Structures of Ionic Liquids with Different Anions Studied by Infrared Vibration Spectroscopy

Cited by 269 publications

References 40 publications

Interaction of Water Vapor with the Surfaces of Imidazolium-Based Ionic Liquid Nanoparticles and Thin Films

Interaction of Water Vapor with the Surfaces of Imidazolium-Based Ionic Liquid Nanoparticles and Thin Films

Decorating Semiconductor Silver-Tetracyanoquinodimethane Nanowires with Silver Nanoparticles from Ionic Liquids

Robust and versatile ionic liquid microarrays achieved by microcontact printing

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