共查询到20条相似文献,搜索用时 10 毫秒
1.
Dr. Ulrich P. Preiss Dr. Dzmitry H. Zaitsau Dr. Witali Beichel Dr. Daniel Himmel Dr. Alexander Higelin Dr. Klaus Merz Niklas Caesar Prof. Dr. Sergey P. Verevkin 《Chemphyschem》2015,16(13):2890-2898
New measurements of vaporization enthalpies for 15 1:1 ionic liquids are performed by using a quartz‐crystal microbalance. Collection and analysis of 33 available crystal structures of organic salts, which comprise 13 different cations and 12 anions, is performed. Their dissociation lattice enthalpies are calculated by a combination of experimental and quantum chemical quantities and are divided into the relaxation and Coulomb components to give an insight into elusive short‐range interaction enthalpies. An empirical equation is developed, based on interaction‐specific Hirshfeld surfaces and solvation enthalpies, which enables the estimation of the lattice enthalpy by using only the crystal‐structure data. 相似文献
2.
Metallosurfactant Ionogels in Imidazolium and Protic Ionic Liquids as Precursors To Synthesize Nanoceria as Catalase Mimetics for the Catalytic Decomposition of H2O2 下载免费PDF全文
Xiaolin Wang Qiao Yang Yixue Cao Haibin Hao Junhan Zhou Prof. Dr. Jingcheng Hao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(49):17857-17865
The gelation behavior of cationic surfactants with different counterions, Br?, [FeCl3Br]?, and [CeCl3Br]?, in imidazolium ionic liquids (ILs) and protic ethylammonium nitrate was investigated. Small‐angle X‐ray scattering measurements and freeze‐fracture transmission electron microscopy observations revealed the lamellar phases of metallosurfactant ionogels. The characteristics of imidazolium ILs, including the size and type, have effects on metallosurfactant ionogel properties, such as transformation temperatures, interlayer spacing, and mechanical strength. Cubic fluorite structured cerium oxide nanoparticles (CeO2 NPs) were produced by using metallosurfactant ionogels as precursors. Cubic fluorite CeO2 exhibited good catalase mimetic activity toward H2O2 to generate O2, providing more multiple mimetic enzyme activities of CeO2 NPs for H2O2. 相似文献
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The ultrafast excited‐state dynamics of a fibril binding dye, thioflavin T (ThT), has been studied in two room‐temperature ionic liquids (RTILs): 1‐Butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and methyltrioctylammonium bis(trifluoromethylsulfonyl)imide. Previously, in most studies, it was observed that the excited‐state dynamics of the ThT dye were dependent on the viscosity of the medium. In our study, by using RTILs, we have demonstrated that the excited‐state dynamics of ThT are not only viscosity dependent, but also dependent on the heterogeneous nature of the medium. The effect of structural heterogeneity present in neat RTILs on the excited‐state dynamics of ThT was observed. For both RTILs, excitation wavelength dependency on the emission properties of ThT was observed. 相似文献
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Ariel I. Horowitz Prof. Matthew J. Panzer 《Angewandte Chemie (International ed. in English)》2014,53(37):9780-9783
The immiscibility of poly(dimethylsiloxane) (PDMS) and ionic liquids (ILs) was overcome to create PDMS‐supported IL gels (ionogels) with IL loadings of up to 80 % by mass through a simple sol–gel reaction at room temperature. By stirring a mixture of a functionalized PDMS oligomer, formic acid, and an IL (or lithium‐in‐IL solution), a resin was formed that could be cast to create a freestanding, flexible ionogel. PDMS‐supported ionogels exhibited favorable ionic conductivity (ca. 3 mS cm?1) and excellent mechanical behavior (elastic modulus: ca. 60 kPa; fatigue life: >5000 cycles; mechanically stable at temperatures up to 200 °C). The activation energy of ionic conductivity was shown to be nearly identical for the ionogel and the neat IL, in contrast to ionogel systems wherein the scaffold material is miscible with the IL. This similarity indicates that IL/scaffold chemical interactions are key to the understanding of ionogel electrical performance, especially at elevated temperatures. 相似文献
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Lanthanide Luminescence Improvement by Using a Functional Poly(Ionic Liquid) as Matrix and Co‐ligand 下载免费PDF全文
A poly(ionic liquid) (BA‐PIL) carrying a benzoic acid group in each repeating unit of the polymer architecture, which has the dual function of acting as a matrix and second ligand, has been developed. Through the incorporation of BA‐PIL with the complex [Ln(hfa)3] (hfa=hexafluoroacetylacetone) as an emitting precursor, significant luminescence improvement was achieved in the obtained hybrid materials. Confinement of the lanthanide(III) complexes within the rigid chains of the polymer, together with replacement of the coordinated water molecules, are believed to be ascribed to the enhanced optical properties. 相似文献
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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
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Dr. Raul Porcar Dr. Nicolás Ríos‐Lombardía Dr. Eduardo Busto Dr. Vicente Gotor‐Fernández Dr. Jose Montejo‐Bernardo Prof. Santiago García‐Granda Prof. Santiago V. Luis Prof. Vicente Gotor Dr. Ignacio Alfonso Dr. Eduardo García‐Verdugo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(3):892-904
An exhaustive experimental study based on X‐ray diffraction analysis, NMR, FTIR‐ATR (attenuated total reflection), and Raman spectroscopy as well as theoretical calculations is reported in order to understand how the non‐covalent intermolecular contacts are fundamental to explain structure–property relationships and allowing us to correlate a basic macroscopic property (i.e., the melting point, Tm) with the structural variables of a family of enantiopure 1,4‐dialkyl‐1,2,4‐triazolium salts. The effect of different structural vectors such as the ring size, the spatial disposition of the substituent, the substitution on the oxygen atom, the nature of the anion, or the N4 alkylation of the triazole on the intermolecular interactions of these chiral salts of a well‐defined 3D structure is reported. The non‐covalent intermolecular contacts mainly implicating the triazolium H3 proton are fundamental to explain structure–property relationships and, therefore, the physical properties of these new chiral salts, rather than simple anion–cation interactions. Overall, our findings highlight the importance of the specific supramolecular interactions for the understanding of the physical properties of triazolium salts and ionic liquids. 相似文献
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Ionic liquids (ILs) are recognized as an environmentally friendly alternative to replacing volatile molecular solvents. Knowledge of vaporization thermodynamics is crucial for practical applications. The vaporization thermodynamics of five ionic liquids containing a pyridinium cation and the [NTf2] anion were studied using a quartz crystal microbalance. Vapor pressure-temperature dependences were used to derive the enthalpies of vaporization of these ionic liquids. Vaporization enthalpies of the pyridinium-based ionic liquids available in the literature were collected and uniformly adjusted to the reference temperature T = 298.15 K. The consistent sets of evaluated vaporization enthalpies were used to develop the “centerpiece”-based group-additivity method for predicting enthalpies of vaporization of ionic compounds. The general transferability of the contributions to the enthalpy of vaporization from the molecular liquids to the ionic liquids was established. A small, but not negligible correction term was supposed to reconcile the estimated results with the experiment. The corrected “centerpiece” approach was recommended to predict the vaporization enthalpies of ILs. 相似文献
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Ftima A. R. Mota Sarah A. P. Pereira Andr R. T. S. Araujo M. Lúcia M. F. S. Saraiva 《Molecules (Basel, Switzerland)》2021,26(1)
Human neutrophil elastase (HNE) is used as diagnostic biomarker for inflammation/infection. In this work, 10 ionic liquids (ILs) and 11 ionic liquids active pharmaceutical ingredients (ILs-APIs) were tested to evaluate the inhibition effect on the activity of porcine pancreatic elastase enzyme, frequently employed as a model for HNE. The insertion of ionic liquids in some drugs is useful, as the insertion of ILs with inhibitory capacity will also slow down all processes in which this enzyme is involved. Therefore, a spectrophotometric method was performed to the determination of EC50 values of the compounds tested. EC50 values of 124 ± 4 mM to 289 ± 11 mM were obtained, with the most toxic IL for elastase being tetrabutylammonium acetate and the least toxic 1-butyl-3-methylimidazolium acetate. Moreover, sodium salicylate (raw material) presented the lower and benzethonium bistriflimide the higher EC50 when compared with all the IL-APIs tested. This work provides significant information about the effect of the studied IL and IL-APIs in elastase enzyme activity. 相似文献
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离子液体独特的物理化学性质,使其成为应用前景良好的绿色功能材料和介质,受到广泛关注。本文探讨了离子液体结构-性质关系及现存的问题,对相关实验和理论工作进行了分析;揭示了离子液体的多尺度结构和动态变化规律,构建离子液体微观结构与宏观性质之间的定量关系,为离子液体体系定量设计与调控提供了科学理论和方法;展望了离子液体在化工、能源、环境和材料等领域的应用。 相似文献
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Towards the Application of Structure–Property Relationship Modeling in Materials Science: Predicting the Seebeck Coefficient for Ionic Liquid/Redox Couple Systems 下载免费PDF全文
Dr. Anita Sosnowska Maciej Barycki Dr. Agnieszka Gajewicz Dr. Maciej Bobrowski Dr. Sylwia Freza Prof. Piotr Skurski Stefanie Uhl Edith Laux Tony Journot Laure Jeandupeux Prof. Herbert Keppner Dr. Tomasz Puzyn 《Chemphyschem》2016,17(11):1591-1600
This work focuses on determining the influence of both ionic‐liquid (IL) type and redox couple concentration on Seebeck coefficient values of such a system. The quantitative structure–property relationship (QSPR) and read‐across techniques are proposed as methods to identify structural features of ILs (mixed with LiI/I2 redox couple), which have the most influence on the Seebeck coefficient (Se) values of the system. ILs consisting of small, symmetric cations and anions with high values of vertical electron binding energy are recognized as those with the highest values of Se. In addition, the QSPR model enables the values of Se to be predicted for each IL that belongs to the applicability domain of the model. The influence of the redox‐couple concentration on values of Se is also quantitatively described. Thus, it is possible to calculate how the value of Se will change with changing redox‐couple concentration. The presence of the LiI/I2 redox couple in lower concentrations increases the values of Se, as expected. 相似文献
13.
Ting He Cheng-Bin Hong Peng-Chong Jiao Heng Xiang Yan Zhang Hua-Qiang Cai Shuang-Long Wang Guo-Hong Tao 《Molecules (Basel, Switzerland)》2021,26(1)
[AAE]X composed of amino acid ester cations is a sort of typically “bio-based” protic ionic liquids (PILs). They possess potential Brønsted acidity due to the active hydrogens on their cations. The Brønsted acidity of [AAE]X PILs in green solvents (water and ethanol) at room temperature was systematically studied. Various frameworks of amino acid ester cations and four anions were investigated in this work from the viewpoint of structure–property relationship. Four different ways were used to study the acidity. Acid dissociation constants (pKa) of [AAE]X determined by the OIM (overlapping indicator method) were from 7.10 to 7.73 in water and from 8.54 to 9.05 in ethanol. The pKa values determined by the PTM (potential titration method) were from 7.12 to 7.82 in water. Their Hammett acidity function (H0) values (0.05 mol·L−1) were about 4.6 in water. In addition, the pKa values obtained by the DFT (proton-transfer reactions) were from 7.11 to 7.83 in water and from 8.54 to 9.34 in ethanol, respectively. The data revealed that the cationic structures of [AAE]X had little effect and the anions had no effect on the acidity of [AAE]X. At the same time, the OIM, PTM, Hammett method and DFT method were reliable for determining the acidic strength of [AAE]X in this study. 相似文献
14.
Yan An GAO Zhong Ni WANG Jin ZHANG Wan Guo HOU Gan Zuo LI* Bu Xing HAN* Feng Feng Lü Gao Yong ZHANG Key Laboratory of Colloid Interface Chemistry 《中国化学快报》2005,16(7):963-966
The surfactant TX-100 can be dissolved in ionic liquid bmimPF6 and decrease the surface tension of 1-buty1-3-methylimidazolium hexafluorophosphate (bmimPF6) solutions. Here, we confirmed that in this new system, the pure solvents need rearrangement at the air-wate rinterface at the initial stage. The dynamic surface tension (DST) study shows that at the initial adsorption stage, the adsorption model of surfactant accords with the diffusion-controlled adsorption mechanism, and the dilute ionic liquids solutions is further close to the diffusion-controlled adsorption. 相似文献
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离子液体作为潜在的“绿色”溶剂,具有许多传统溶剂无法比拟的优异性能,在有机合成、催化、液液分离和萃取等领域引起了广泛的研究。而在离子液体领域无机材料的制备是一个较新的发展分支,现已利用其合成出多种具有独特结构和性能的无机材料。本文就离子液体在无机材料制备方面的应用及发展趋势进行了综述。目前,对于制备无机材料,离子液体主要是作为电解液、表面活性剂或溶剂,本文介绍了其在应用中的优缺点,并指出该领域未来的发展趋势是离子热合成和集模板-溶剂-反应物于一身的离子液体反应。 相似文献
18.
Three new hybrid ionic liquids (ILs) based on cage silsesquioxane (SQ) were rapidly prepared in high yields from octa(mercaptopropyl)silsesquioxane and 1‐allyl‐3‐methylimidazolium salts (Br?, BF4?, PF6?) through the photochemical thiol–ene reaction. These SQ‐based ILs exhibited low glass transition temperatures and good thermal stability. The unique amphiphilic nature of these hybrid ILs cause them to self‐assemble into perfect vesicles with “yolk–shell” structures, in which cages formed the “yolk” due to their aggregation and outer anions formed the “shell”. 相似文献
19.
Satyam Srivastava Alexander E. Ribbe Thomas P. Russell David A. Hoagland 《Journal of polymer science. Part A, Polymer chemistry》2020,58(3):478-486
Crystals of poly(ethylene glycol) grown in thin films of the room temperature ionic liquid (IL) 1-ethyl-3-methylimidazolium ethyl sulfate were examined by electron microscopy as a first step toward exploiting nonvolatile liquids for nanoscale imaging of solvated/dissolved polymeric materials. The crystals were generated by cooling supported (over surfaces of varied polarity) and freestanding solution films to room temperature. This “open,” that is, without liquid cell, microscopy was performed on unstained, as-grown crystals in the presence of the IL. A variety of nearly two-dimensional crystal morphologies were observed, including rods, fibers, spherulites, compact faceted single crystals, and interconnected networks, with characteristic sizes ranging from tens of nanometers to tens of microns. Electron diffraction patterns for the rods and fibers revealed single crystal-like long-range order. The nature of the IL support little affected the morphology, but film thickness and cooling rate proved important. To assess the role of solvent polarity, crystals were also grown from 1-ethyl-3-methylimidazolium ethyl sulfate mixed with the second IL, the less polar ethyl-tributyl-phosphonium diethyl phosphate; here, although the morphologies were similar to those made with pure IL, fibrillar morphologies were more prevalent. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 478–486 相似文献