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1.
Jun Li Jintao Zhang Zhengping Liu 《Journal of polymer science. Part A, Polymer chemistry》2006,44(15):4420-4427
Conventional free‐radical copolymerization of acrylonitrile (AN) and styrene (St) was realized in room temperature ionic liquids (RTILs), 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([Bmim][BF4]) and 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([Bmim][PF6]), under mild conditions. The copolymerization in RTILs was more rapid than that in traditional solvent DMF. Poly(styrene‐co‐acrylonitrile) (SAN) prepared in RTILs had higher molecular weight than that prepared in DMF or by bulk copolymerization. SAN with bimodal molecular weight distribution (MWD) were obtained in most of the reaction conditions in [Bmim][BF4] and some conditions in [Bmim][PF6]. By the analysis of reaction phenomena and fluorescence behavior, the reason of the difference in MWD could be attributed to the difference of reaction system compatibility mainly caused by the immiscibility of macromolecule with RTIL. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4420–4427, 2006 相似文献
2.
Morphology of Imidazolium‐Based Ionic Liquids as Deposited by Vapor Deposition: Micro‐/Nanodroplets and Thin Films 下载免费PDF全文
Dr. José C. S. Costa Prof. Adélio Mendes Prof. Luís M. N. B. F. Santos 《Chemphyschem》2016,17(14):2123-2127
The morphology of micro‐ and nanodroplets and thin films of ionic liquids (ILs) prepared through physical vapor deposition is presented. The morphology of droplets deposited on indium‐tin‐oxide‐coated glass is presented for the extended 1‐alkyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([CnC1im][Ntf2]; n=1–8) series, and the results show the nanostructuration of ILs. The use of in‐vacuum energetic particles enhances/increases the nanodroplets mobility/coalescence mechanisms and can be a pathway to the fabrication of thin IL films. 相似文献
3.
Aleksandra Maršavelski Dr. Vilko Smrečki Dr. Robert Vianello Prof. Dr. Mladen Žinić Prof. Dr. Andrea Moguš‐Milanković Dr. Ana Šantić 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(34):12121-12128
Supramolecular ionogels were prepared by the gelation of room‐temperature ionic liquid 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIm][BF4]) with (S,S)‐bis(leucinol)oxalamide. Remarkably, the ionic conductivity of solutions and ionogels with low gelator concentrations is higher than that of neat [BMIm][BF4]. On the basis of molecular dynamics simulations and quantum mechanical calculations, the origin of this phenomenon is attributed to the higher affinity of gelator molecules towards [BF4]? ions, which reduces the electrostatic attraction between [BMIm]+ and [BF4]? and thus increases their mobility. With increasing gelator concentration, the ionic conductivity decreases due to the formation of a denser gelator matrix, which hinders the pathways for ionic transport. However, even for very dense ionogels, this decrease is less than one order of magnitude relative to neat [BMIm][BF4], and thus they can be classified as highly conductive materials with strong potential for application as functional electrolytes. 相似文献
4.
Radha G. Bhuin Leonhard Winter Matthias Lexow Florian Maier Hans‐Peter Steinrück 《Angewandte Chemie (International ed. in English)》2020,59(34):14429-14433
The impact of a reactant from the gas phase on the surface of a liquid and its transfer through this gas/liquid interface are crucial for various concepts applying ionic liquids (ILs) in catalysis. We investigated the first step of the adsorption dynamics of n‐butane on a series of 1‐alkyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide ILs ([CnC1Im][Tf2N]; n=1, 2, 3, 8). Using a supersonic molecular beam in ultra‐high vacuum, the trapping of n‐butane on the frozen ILs was determined as a function of surface temperature, between 90 and 125 K. On the C8‐ and C3‐ILs, n‐butane adsorbs at 90 K with an initial trapping probability of ≈0.89. The adsorption energy increases with increasing length of the IL alkyl chain, whereas the ionic headgroups seem to interact only weakly with n‐butane. The absence of adsorption on the C1‐ and C2‐ILs is attributed to a too short residence time on the IL surface to form nuclei for condensation even at 90 K. 相似文献
5.
Susana Chatzipapadopoulos Tobias Zentel Prof. Dr. Ralf Ludwig Matthias Lütgens Prof. Dr. Stefan Lochbrunner Prof. Dr. Oliver Kühn 《Chemphyschem》2015,16(12):2519-2523
Understanding both structure and dynamics is crucial for producing tailor‐made ionic liquids (ILs). We studied the vibrational and structural dynamics of medium versus weakly hydrogen‐bonded C?H groups of the imidazolium ring in ILs of the type [1‐alkyl‐3‐methylimidazolium][bis(trifluoromethanesulfonyl)imide] ([Cnmim][NTf2]), with n=1, 2, and 8, by time‐resolved coherent anti‐Stokes Raman scattering (CARS) and quantum‐classical hybrid (QCH) simulations. From the time series of the CARS spectra, dephasing times were extracted by modeling the full nonlinear response. From the QCH calculations, pure dephasing times were obtained by analyzing the distribution of transition frequencies. Experiments and calculations reveal larger dephasing rates for the vibrational stretching modes of C(2)?H compared with the more weakly hydrogen‐bonded C(4,5)?H. This finding can be understood in terms of different H‐bonding motifs and the fast interconversion between them. Differences in population relaxation rates are attributed to Fermi resonance interactions. 相似文献
6.
NMR Diffusion Measurements as a Simple Method to Examine Solvent–Solvent and Solvent–Solute Interactions in Mixtures of the Ionic Liquid [Bmim][N(SO2CF3)2] and Acetonitrile 下载免费PDF全文
Dr. Sinead T. Keaveney Karin S. Schaffarczyk McHale Dr. James W. Stranger Dr. Batchimeg Ganbold Prof. William S. Price Prof. Jason B. Harper 《Chemphyschem》2016,17(23):3853-3862
The self‐diffusion coefficients of each component in mixtures of 1‐butyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide ([Bmim][N(SO2CF3)2]) and acetonitrile were determined. The results suggest that the hydrodynamic boundary conditions change from “stick” to “slip” as the solvent composition transitions from “ionic liquid dissolved in acetonitrile” (χIL<0.4) to “acetonitrile dissolved in ionic liquid” (χIL>0.4). At higher χIL, the acetonitrile species are affected by “cage” and “jump” events, as the acetonitrile molecules reside nearer to the charged centre on the ions than in the “non‐polar” regions. The self‐diffusion coefficients of hexan‐1‐amine, dipropylamine, 1‐hexanol and dipropylether in mixtures of [Bmim][N(SO2CF3)2] and acetonitrile were determined. In general, the nitrogen‐containing solutes were found to diffuse slower than the oxygen‐containing solutes; this indicates that there are greater ionic liquid–N interactions than ionic liquid–O interactions. This work demonstrates that the self‐diffusion coefficients of species can provide valuable information about solvent–solvent and solvent–solute interactions in mixtures containing an ionic liquid. 相似文献
7.
Synthesis and Characterisation of Fluorescent Carbon Nanodots Produced in Ionic Liquids by Laser Ablation 下载免费PDF全文
M. Sc. Hemerson P. S. Castro Dr. Virgínia S. Souza Prof. Dr. Jackson D. Scholten Janine H. Dias Dr. Jesum A. Fernandes Prof. Dr. Fabiano S. Rodembusch Dr. Roberto dos Reis Prof. Dr. Jairton Dupont Prof. Dr. Sérgio R. Teixeira Prof. Dr. Ricardo R. B. Correia 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(1):138-143
Carbon nanodots (C‐dots) with an average size of 1.5 and 3.0 nm were produced by laser ablation in different imidazolium ionic liquids (ILs), namely, 1‐n‐butyl‐3‐methylimidazolium tetrafluoroborate (BMI.BF4), 1‐n‐butyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide (BMI.NTf2) and 1‐n‐octyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide (OMI.NTf2). The mean size of the nanoparticles is influenced by the imidazolium alkyl side chain but not by the nature of the anion. However, by varying the anion (BF4 vs. NTf2) it was possible to detect a significant modification of the fluorescence properties. The C‐dots are much probably stabilised by an electrostatic layer of the IL and this interaction has played an important role with regard to the formation, stabilisation and photoluminescence properties of the nanodots. A tuneable broadband fluorescence emission from the colloidal suspension was observed under ultraviolet/visible excitation with fluorescence lifetimes fitted by a multi‐exponential decay with average values around 7 ns. 相似文献
8.
Karla A. Barrera‐Rivera Ángel Marcos‐Fernández Ricardo Vera‐Graziano Antonio Martínez‐Richa 《Journal of polymer science. Part A, Polymer chemistry》2009,47(21):5792-5805
Yarrowia lipolytica (YLL), Candida rugosa (CRL), and porcine pancreatic lipase (PPL) were employed successfully as catalysts in the enzymatic ring‐opening polymerization (ROP) of ε‐caprolactone in the presence of 1‐ethyl‐3‐methylimidazolium tetrafluoroborate ([EMIM][BF4]), 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIM][BF4]), 1‐butylpyridinium tetrafluoroborate ([BuPy][BF4]), 1‐butylpyridinium trifluoroacetate ([BuPy][CF3COO]), 1‐ethyl‐3‐methylimidazolium nitrate ([EMIM][NO3]) ionic liquids. Poly(ε‐caprolactone)s (PCLs) with molecular weights (Mn) in the range of 300–9000 Da were obtained. 1H‐ and 13C‐NMR analyses on PCLs formed by YLL, CRL, and PPL showed asymmetric telechelic α‐hydroxy‐ω‐carboxylic acid end groups. Differences between CP‐MAS and MAS spectra are observed and discussed in terms of morphology. MALDI‐TOF spectra show the formation of at least seven species. Differential scanning calorimetry (DSC) and Wide Angle X‐Ray Scattering (WAXS) results demonstrate the high degree of crystallinity present in all the polyesters. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5792–5805, 2009 相似文献
9.
The behavior of an ionic liquid (IL) within aqueous micellar solutions is governed by its unique property to act as both an electrolyte and a cosolvent. The influence of the surfactant structure on the properties of aqueous micellar solutions of zwitterionic SB‐12, nonionic Brij‐35 and TX‐100, and anionic sodium dodecyl sulfate (SDS) in the presence of the “hydrophobic” IL 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim][PF6]) is assessed along with the possibility of forming oil‐in‐water microemulsions in which the IL acts as the “oil” phase. The solubility of [bmim][PF6] within aqueous micellar solutions increases with increasing surfactant concentration. In contrast to anionic SDS, the zwitterionic and nonionic surfactant solutions solubilize more [bmim][PF6] at higher concentrations and the average aggregate size remains almost unchanged. The formation of IL‐in‐water microemulsions when the concentration of [bmim][PF6] is above its aqueous solubility is suggested for nonionic Brij‐35 and TX‐100 aqueous surfactant solutions. 相似文献
10.
The molecular interactions of the ionic liquids (ILs) 1‐butyl‐3‐methylimidazolium tetrafluoroborate [C4mim][BF4], 3‐methyl‐1‐octylimidazolium tetrafluoroborate [C8mim][BF4] and 1‐butyl‐3‐methylimidazolium octylsulfate [C4mim][C8OSO3] are investigated in ethylene glycol (EG) over the whole mole fraction range using fluorescence (steady‐state and time‐resolved), Fourier transform infrared and nuclear magnetic resonance (NMR) spectroscopy. The cybotactic region surrounding the pyrene fluorescent probe exhibits peculiar characteristics for different ILs in the EG‐rich region. The extent of solute–solvent interactions is assessed by determining the deviations of experimentally observed vibronic band intensity ratios of peak 1 to peak 3 of pyrene fluorescence (I1/I3) from a composite I1/I3 value obtained using a preferential solvation model. A distinct vibrational frequency shift for various stretching modes of EG (O? H) or ILs (C? H of ring protons, B? F and S?O of anions) indicates specific interactional preferences of EG toward the IL protons/anion. Splitting of the O? H vibration band of EG at 3000–3700 cm?1 into three separate bands, and analysis of the changes in location and area of these bands as a function of concentration enable precise determination of the effect of ILs on hydrogen bridges of EG. NMR chemical shifts and their deviations from ideality show multiple hydrogen‐bonding interactions of varying strengths between unlike molecules in the mixtures. A comparison of spectroscopic results with thermodynamic properties shows that the mixing microscopic behaviour of the investigated systems is completely different from the macroscopic behaviour, which is primarily governed by the difference in shape, size and nature of the molecules. 相似文献
11.
Dr. Xiaochuan Duan Dr. Di Li Dr. Huili Zhang Dr. Jianmin Ma Prof. Dr. Wenjun Zheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(22):7231-7242
In the work presented here, well‐dispersed ferric giniite microcrystals with controlled sizes and shapes are solvothermally synthesized from ionic‐liquid precursors by using 1‐n‐butyl‐3‐methylimidazolium dihydrogenphosphate ([Bmim][H2PO4]) as phosphate source. The success of this synthesis relies on the concentration and composition of the ionic‐liquid precursors. By adjusting the molar ratios of Fe(NO3)3 ? 9H2O to [Bmim][H2PO4] as well as the composition of ionic‐liquid precursors, we obtained uniform microstructures such as bipyramids exposing {111} facets, plates exposing {001} facets, hollow spheres, tetragonal hexadecahedron exposing {441} and {111} facets, and truncated bipyamids with carved {001} facets. The crystalline structure of the ferric giniite microcrystals is disclosed by various characterization techniques. It was revealed that [Bmim][H2PO4] played an important role in stabilizing the {111} facets of ferric giniite crystals, leading to the different morphologies in the presence of ionic‐liquid precursors with different compositions. Furthermore, since these ferric giniite crystals were characterized by different facets, they could serve as model Fenton‐like catalysts to uncover the correlation between the surface and the catalytic performance for the photodegradation of organic dyes under visible‐light irradiation. Our measurements indicate that the photocatalytic activity of as‐prepared Fenton‐like catalysts is highly dependent on the exposed facets, and the surface area has essentially no obvious effect on the photocatalytic degradation of organic dyes in the present study. It is highly expected that these findings are useful in understanding the photocatalytic activity of Fenton‐like catalysts with different morphologies, and suggest a promising new strategy for crystal‐facet engineering of photocatalysts for wastewater treatment based on heterogeneous Fenton‐like process. 相似文献
12.
13.
Huiyong Wang Jianji Wang Prof. Dr. Sheli Zhang Yuanchao Pei Dr. Kelei Zhuo Prof. Dr. 《Chemphyschem》2009,10(14):2516-2523
Considering the ionic nature of ionic liquids (ILs), ionic association is expected to be essential in solutions of ILs and to have an important influence on their applications. Although numerous studies have been reported for the ionic association behavior of ILs in solution, quantitative results are quite scarce. Herein, the conductivities of the ILs [Cnmim]Br (n=4, 6, 8, 10, 12), [C4mim][BF4], and [C4mim][PF6] in various molecular solvents (water, methanol, 1‐propanol, 1‐pentanol, acetonitrile, and acetone) are determined at 298.15 K as a function of IL concentration. The conductance data are analyzed by the Lee–Wheaton conductivity equation in terms of the ionic association constant (KA) and the limiting molar conductance (Λm0). Combined with the values for the Br? anion reported in the literature, the limiting molar conductivities and the transference numbers of the cations and [BF4]? and [PF6]? anions are calculated in the molecular solvents. It is shown that the alkyl chain length of the cations and type of anion affect the ionic association constants and limiting molar conductivities of the ILs. For a given anion (Br?), the Λm0 values decrease with increasing alkyl chain length of the cations in all the molecular solvents, whereas the KA values of the ILs decrease in organic solvents but increase in water as the alkyl chain length of the cations increases. For the [C4mim]+ cation, the limiting molar conductivities of the ILs decrease in the order Br?>[BF4]?>[PF6]?, and their ionic association constants follow the order [BF4]?>[PF6]?>Br? in water, acetone, and acetonitrile. Furthermore, and similar to the classical electrolytes, a linear relationship is observed between ln KA of the ILs and the reciprocal of the dielectric constants of the molecular solvents. The ILs are solvated to a different extent by the molecular solvents, and ionic association is affected significantly by ionic solvation. This information is expected to be useful for the modulation of the IL conductance by the alkyl chain length of the cations, type of anion, and physical properties of the molecular solvents. 相似文献
14.
Steady‐state and time‐resolved fluorescence behavior of coumarin 153 (C153) is investigated in a series of 1‐ethyl‐3‐methylimidazolium alkylsulfate ([C2mim][CnOSO3]) ionic liquids differing only in the length of the linear alkyl chain (n=4, 6, and 8) in the anion. The aim of the present study is to understand the role of alkyl chain length in solute rotation and solvation dynamics of C153 in these ionic liquids. The blueshift observed in the steady‐state absorption and emission maxima of C153 on going from the C4OSO3 to the C8OSO3 system indicates increasing nonpolar character of the microenvironment of the solute with increasing length of the alkyl side chain of the anion of the ionic liquids. The average solvation time is also found to increase on changing the substituent from butyl to octyl, and this is attributed to the increase in the bulk viscosity of the ILs. A steady blueshift of the time‐zero maximum of the fluorescence spectrum with increasing alkyl chain length also indicates that the probe molecule experiences a less polar environment in the early part of the dynamics. Rotational dynamics of C153 are also analyzed by using the Stokes–Einstein–Debye (SED), Gierer–Wirtz (GW), and Dote–Kivelson–Schwartz (DKS) theories. Analyses of the results seem to suggest decoupling of the rotational motion of the probe from solvent viscosity. 相似文献
15.
Pummerer‐type reaction was carried out with α‐acyl sulfides and phenyliodine(III) bis(trifluoroacetate) (PIFA) instead of α‐acyl sulfoxides in the room temperature ionic liquid 1‐n‐butyl‐3‐methylimidazolium hexafluorophosphate [bmim][PF6] under mild conditions to give the ene adducts 3 in good yields. 相似文献
16.
Soumya S. Sarangi Wei Zhao Dr. Florian Müller‐Plathe Prof. Dr. Sundaram Balasubramanian Prof. 《Chemphyschem》2010,11(9):2001-2010
The complex dynamics of a room‐temperature ionic liquid, 1‐n‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim][PF6]), is studied using equilibrium classical molecular dynamics simulations in the temperature range of 250–450 K. The activation energies for the self‐diffusion of ions are around 30–34 kJ mol?1, with that of the anion a little higher than that for the cation. The electrical conductivity of the liquid is calculated and good agreement with experiments is obtained. Structural relaxation is studied through the decay of coherent (total density–density correlation) and incoherent (self part of density–density correlation) intermediate scattering functions over a range of temperatures and wave vectors relevant to the system. The relaxation data are used to identify and characterize two processes, α and β. The dependence of the two relaxation times on temperature and wave vector is obtained. The dynamical heterogeneity of the ions determined through the non‐Gaussian parameter indicates the motion of the cation to be more heterogeneous than that of the anion. The faster ones among the cations are coordinated to faster anions, while slower cations are surrounded predominantly by slower anions. Thus, the dynamical heterogeneity in this ionic liquid is shown to have structural signatures. 相似文献
17.
X‐ray Photoelectron Spectroscopy of Pyridinium‐Based Ionic Liquids: Comparison to Imidazolium‐ and Pyrrolidinium‐Based Analogues 下载免费PDF全文
Shuang Men Daniel S. Mitchell Kevin R. J. Lovelock Peter Licence 《Chemphyschem》2015,16(10):2211-2218
We investigate eight 1‐alkylpyridinium‐based ionic liquids of the form [CnPy][A] by using X‐ray photoelectron spectroscopy (XPS). The electronic environment of each element of the ionic liquids is analyzed. In particular, a reliable fitting model is developed for the C 1s region that applies to each of the ionic liquids. This model allows the accurate charge correction of binding energies and the determination of reliable and reproducible binding energies for each ionic liquid. Shake‐up/off phenomena are determinedfor both C 1s and N 1s spectra. The electronic interaction between cations and anions is investigated for both simple ionic liquids and an example of an ionic‐liquid mixture; the effect of the anion on the electronic environment of the cation is also explored. Throughout the study, a detailed comparison is made between [C8Py][A] and analogues including 1‐octyl‐1‐methylpyrrolidinium‐ ([C8C1Pyrr][A]), and 1‐octyl‐3‐methylimidazolium‐ ([C8C1Im][A]) based samples, where X is common to all ionic liquids. 相似文献
18.
Pyrano[2,3‐d]pyrimidine derivatives were synthesized in high yields by a condensation reaction between arylmethylidenemalononitrile and barbituric acid using room‐temperature ionic liquids such as 1‐n‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIm]BF4) or 1‐butylpyridinium tetrafluoroborate ([BPy]BF4) as solvents under neutral conditions. 相似文献
19.
A palladium nanoparticle catalyst (PdNPs@[Bmim]Lac) has been prepared by a simple, mild and efficient chemical approach using 1‐butyl‐3‐methylimidazolium lactate ([Bmim]Lac) ionic liquid) as a stabilizer. This catalyst exhibits excellent activity, stability, recyclability and simple manipulation in Suzuki‐Miyaura reactions at room temperature in air. 相似文献
20.
Multilayers of myoglobin (Mb) with ionic liquid 1‐ethyl‐3‐methylimidazolium tetrafluoroborate ([EMIM]BF4) was assembled on carbon ionic liquid electrode (CILE) based on the electrostatic attraction between the negatively charged Mb and the positively charged imidazolium ion of IL. The CILE was fabricated with 1‐ethyl‐3‐methylimidazolium ethylsulfate ([EMIM]EtOSO3) as the modifier, which exhibited imidazolium ion on the electrode surface. Then Mb molecules were assembled on the surface of CILE step‐by‐step to get a {IL/Mb}n multilayer film modified electrode. UV‐Vis adsorption and FT‐IR spectra indicated that Mb remained its native structure in the IL matrix. In deaerated phosphate buffer solution (pH 7.0) a pair of well‐defined quasi‐reversible redox peaks appeared with the apparent formal potential (E0′) as ‐0.212 V (vs. SCE), which was the characteristic of Mb heme Fe(III)/Fe(II) redox couples. The results indicated that the direct electron transfer of Mb was realized on the modified electrode. The {IL/Mb}n/CILE displayed excellent electrocatalytic ability to the trichloroacetic acid reduction in the concentration range from 2.0 to 22.0 mmol/L with the detection limit of 0.6 mmol/L (3σ). The proposed method provides a new platform to fabricate the third generation biosensor based on the self‐assembly of redox protein with ILs. 相似文献