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Zhao, Hua, Caden Martin, Gary Baker et Katie Mitchell-Koch. « (Invited) Functionalized Water-Mimicking Ionic Liquids for Biocatalysis ». ECS Meeting Abstracts MA2022-02, no 55 (9 octobre 2022) : 2116. http://dx.doi.org/10.1149/ma2022-02552116mtgabs.
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Enzyme activity in organic solvents is usually much lower than its performance in aqueous media. To develop water-mimicking environment for the enzyme, we designed ionic liquids functionalized with tert-alcohol (as hydrogen-bond donor) and ether groups (as hydrogen-bond acceptors). These “water-like” ionic media have high thermal stability and low viscosities, and produced higher lipase and protease activities and stabilities than some enzyme-compatible organic solvents (such as tert-butanol and diisopropyl ether) and conventional ionic liquids (e.g., [BMIM][Tf2N]) during transesterification reactions under low water contents. In addition, these unique ionic solvents are found suitable media for asymmetric synthesis. Our experimental and MD simulations data illustrate the interactions between these water-mimicking solvent molecules and the enzyme.
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Jing, Jun, Zhiyong Li, Yuanchao Pei, Huiyong Wang et Jianji Wang. « Equilibrium partitioning of drug molecules between aqueous and amino acid ester-based ionic liquids ». Journal of Chemical Thermodynamics 62 (juillet 2013) : 27–34. http://dx.doi.org/10.1016/j.jct.2013.02.011.
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Rodenbücher, Christian, Yingzhen Chen, Klaus Wippermann, Piotr M. Kowalski, Margret Giesen, Dirk Mayer, Florian Hausen et Carsten Korte. « The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy ». International Journal of Molecular Sciences 22, no 23 (23 novembre 2021) : 12653. http://dx.doi.org/10.3390/ijms222312653.
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Protic ionic liquids are promising electrolytes for fuel cell applications. They would allow for an increase in operation temperatures to more than 100 °C, facilitating water and heat management and, thus, increasing overall efficiency. As ionic liquids consist of bulky charged molecules, the structure of the electric double layer significantly differs from that of aqueous electrolytes. In order to elucidate the nanoscale structure of the electrolyte–electrode interface, we employ atomic force spectroscopy, in conjunction with theoretical modeling using molecular dynamics. Investigations of the low-acidic protic ionic liquid diethylmethylammonium triflate, in contact with a platinum (100) single crystal, reveal a layered structure consisting of alternating anion and cation layers at the interface, as already described for aprotic ionic liquids. The structured double layer depends on the applied electrode potential and extends several nanometers into the liquid, whereby the stiffness decreases with increasing distance from the interface. The presence of water distorts the layering, which, in turn, significantly changes the system’s electrochemical performance. Our results indicate that for low-acidic ionic liquids, a careful adjustment of the water content is needed in order to enhance the proton transport to and from the catalytic electrode.
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Khan, Riaz A., Hamdoon A. Mohammed, Ghassan M. Sulaiman, Amal Al Subaiyel, Arjunan Karuppaiah, Habibur Rahman, Sifiso Makhathini, Poornima Ramburrun et Yahya E. Choonara. « Molecule(s) of Interest : I. Ionic Liquids–Gateway to Newer Nanotechnology Applications : Advanced Nanobiotechnical Uses’, Current Status, Emerging Trends, Challenges, and Prospects ». International Journal of Molecular Sciences 23, no 22 (18 novembre 2022) : 14346. http://dx.doi.org/10.3390/ijms232214346.
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Ionic liquids are a potent class of organic compounds exhibiting unique physico-chemical properties and structural compositions that are different from the classical dipolar organic liquids. These molecules have found diverse applications in different chemical, biochemical, biophysical fields, and a number of industrial usages. The ionic liquids-based products and procedural applications are being developed for a number of newer industrial purposes, and academic uses in nanotechnology related procedures, processes, and products, especially in nanobiotechnology and nanomedicine. The current article overviews their uses in different fields, including applications, functions, and as parts of products and processes at primary and advanced levels. The application and product examples, and prospects in various fields of nanotechnology, domains of nanosystem syntheses, nano-scale product development, the process of membrane filtering, biofilm formation, and bio-separations are prominently discussed. The applications in carbon nanotubes; quantum dots; and drug, gene, and other payload delivery vehicle developments in the nanobiotechnology field are also covered. The broader scopes of applications of ionic liquids, future developmental possibilities in chemistry and different bio-aspects, promises in the newer genres of nanobiotechnology products, certain bioprocesses controls, and toxicity, together with emerging trends, challenges, and prospects are also elaborated.
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Cipta, Oktavianus Hendra, Anita Alni et Rukman Hertadi. « Molecular Dynamics Study of Candida rugosa Lipase in Water, Methanol, and Pyridinium Based Ionic Liquids ». Key Engineering Materials 874 (janvier 2021) : 88–95. http://dx.doi.org/10.4028/www.scientific.net/kem.874.88.
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The structure of Candida rugosa lipase can be affected by solvents used in the enzymatic reactions. Using molecular dynamics simulation as a tool to study the Candida rugosa lipase structure, we studied the effect of various solvent systems, such as water, water-methanol, and water-methanol-ionic liquid. These solvent systems have been chosen because lipase is able to function in both aqueous and non-aqueous medium. In this study, pyridinium (Py)-based ionic liquids were selected as co-solvent. The MD simulation was run for 50 nanoseconds for each solvent system at 328 K. In the case of water-methanol-ionic liquids solvent systems, the total number of the ionic liquids added were varied: 222, 444, and 888 molecules. Water was used as the reference solvent system. The structure of Candida rugosa lipase in water-methanol system significantly changed from the initial structure as indicated by the RMSD value, which was about 6.4 Å after 50 ns simulation. This value was relatively higher compared to the other water-methanol solvent system containing ionic liquid as co-solvent, which were 2.43 Å for 4Py-Br, 2.1 Å for 8Py-Br, 3.37 Å for 4Py-BF4 and 3.49 Å for 8Py-BF4 respectively. Further analysis by calculating the root mean square fluctuation (RMSF) of each lipase residue found that the presence of ionic liquids could reduce changes in the enzyme structure. This happened because the anion component of the ionic liquid interacts relatively more strongly with residues on the surface of the protein as compared to methanol, thereby lowering the possibility of methanol to come into contact with the protein.
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Kobayashi, Takeshi, Andre Kemna, Maria Fyta, Björn Braunschweig et Jens Smiatek. « Aqueous Mixtures of Room-Temperature Ionic Liquids : Entropy-Driven Accumulation of Water Molecules at Interfaces ». Journal of Physical Chemistry C 123, no 22 (8 mai 2019) : 13795–803. http://dx.doi.org/10.1021/acs.jpcc.9b04098.
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Kobayashi, Takeshi, Joshua E. S. J. Reid, Seishi Shimizu, Maria Fyta et Jens Smiatek. « The properties of residual water molecules in ionic liquids : a comparison between direct and inverse Kirkwood–Buff approaches ». Physical Chemistry Chemical Physics 19, no 29 (2017) : 18924–37. http://dx.doi.org/10.1039/c7cp03717a.
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Atomistic molecular dynamics simulations of aqueous ionic liquid mixtures were performed in order to compare the resulting Kirkwood–Buff integrals with experimental data and the corresponding integrals derived by an inverse Kirkwood–Buff approach.
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Da Silva, Elianny, Ginebra Sánchez-García, Alberto Pérez-Calvo, Ramón M. Fernández-Domene, Benjamin Solsona et Rita Sánchez-Tovar. « Anodizing Tungsten Foil with Ionic Liquids for Enhanced Photoelectrochemical Applications ». Materials 17, no 6 (8 mars 2024) : 1243. http://dx.doi.org/10.3390/ma17061243.
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This research examines the influence of adding a commercial ionic liquid to the electrolyte during the electrochemical anodization of tungsten for the fabrication of WO3 nanostructures for photoelectrochemical applications. An aqueous electrolyte composed of 1.5 M methanesulfonic acid and 5% v/v [BMIM][BF4] or [EMIM][BF4] was used. A nanostructure synthesized in an ionic-liquid-free electrolyte was taken as a reference. Morphological and structural studies of the nanostructures were performed via field emission scanning electron microscopy and X-ray diffraction analyses. Electrochemical characterization was carried out using electrochemical impedance spectroscopy and a Mott–Schottky analysis. From the results, it is highlighted that, by adding either of the two ionic liquids to the electrolyte, well-defined WO3 nanoplates with improved morphological, structural, and electrochemical properties are obtained compared to samples synthesized without ionic liquid. In order to evaluate their photoelectrocatalytic performance, the samples were used as photocatalysts to generate hydrogen by splitting water molecules and in the photoelectrochemical degradation of methyl red dye. In both applications, the nanostructures synthesized with the addition of either of the ionic liquids showed a better performance. These findings confirm the suitability of ionic liquids, such as [BMIM][BF4] and [EMIM][BF4], for the synthesis of highly efficient photoelectrocatalysts via electrochemical anodization.
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Kawai, Risa, Maiko Niki, Shiho Yada et Tomokazu Yoshimura. « Surface Adsorption Properties and Layer Structures of Homogeneous Polyoxyethylene-Type Nonionic Surfactants in Quaternary-Ammonium-Salt-Type Amphiphilic Gemini Ionic Liquids with Oxygen- or Nitrogen-Containing Spacers ». Molecules 25, no 21 (22 octobre 2020) : 4881. http://dx.doi.org/10.3390/molecules25214881.
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The amphiphilic ionic liquids containing an alkyl chain in molecules form nano-structure in the bulk, although they also show surface activity and form aggregates in aqueous solutions. Although insights into the layer structures of ionic liquids were obtained using X-ray and neutron scattering techniques, the nanostructures of ionic liquids remain unclear. Herein, the surface adsorption and bulk properties of homogeneous polyoxyethylene (EO)-type nonionic surfactants (CxEO6; x = 8, 12, or 16) were elucidated in quaternary-ammonium-salt-type amphiphilic gemini ionic liquids with oxygen or nitrogen-containing spacers [2Cn(Spacer) NTf2; (Spacer) = (2-O-2), (2-O-2-O-2), (2-N-2), (2/2-N-2), (3), (5), or (6); n = 10, 12, or 14 for (2-O-2) and n = 12 for all other spacers] by surface tension, small- and wide-angle X-ray scattering, cryogenic transmission electron microscopy, and viscosity measurements. The surface tension of C12EO6 in 2Cn(Spacer) NTf2 with oxygen-containing spacers increased with increasing concentration of C12EO6, becoming close to that of C12EO6 alone, indicating that the amphiphilic ionic liquid adsorbed at the interface was replaced with CxEO6. In contrast, both 2Cn(Spacer) NTf2 with nitrogen-containing spacers and nonionic surfactants remained adsorbed at the interface at high concentrations. In the bulk, it was found that 2Cn(Spacer) NTf2 formed layer structures, in which the spacing depended on the alkyl chain length of CxEO6. These insights are expected to advance the practical applications of amphiphilic ionic liquids such as ion permeation, drug solubilization, and energy delivery systems.
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Bodachivskyi, Iurii, Unnikrishnan Kuzhiumparambil et D. Bradley G. Williams. « Acid-Catalyzed Conversion of Carbohydrates into Value-Added Small Molecules in Aqueous Media and Ionic Liquids ». ChemSusChem 11, no 4 (5 février 2018) : 642–60. http://dx.doi.org/10.1002/cssc.201702016.
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Mills, Jordan, Gaelle Level, Chirangano Mangwandi et Marijana Blesic. « Aqueous biphasic systems formed in (zwitterionic salt+inorganic salt) mixtures ». Pure and Applied Chemistry 91, no 8 (27 août 2019) : 1351–60. http://dx.doi.org/10.1515/pac-2018-1222.
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Abstract The manuscript reports on a new class of aqueous biphasic systems (ABSs) formed in mixtures of inorganic salts (ISs) and zwitterionic salts (ZWSs). Aqueous ternary phase diagrams characterized by a binodal curve were determined for systems consisting of four ISs, K3PO4, K2HPO4, K2HPO4/KH2PO4, and K2CO3, and three structurally similar ZWSs differing in hydrophobicity. Comparison of phase behaviour of ABSs composed of ZWSs, ionic liquids (ILs) and zwitterions was provided. Potential of ZWSs based systems for extraction of aromatic molecules and amino acids, such as glycine, L-tryptophan, DL-phenylalanine, eugenol, and phenol was examined. Feasibility and limitations of isolation of products after partition and recovery of ZWS were discussed.
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Jacobs, Jeroen, Koen Binnemans et Luc Van Meervelt. « Liquid-liquid solvent extraction of rare earths : a crystallographic analysis. » Acta Crystallographica Section A Foundations and Advances 70, a1 (5 août 2014) : C1006. http://dx.doi.org/10.1107/s2053273314089931.
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Liquid-liquid solvent extraction has become the primary research topic for separating mixtures of rare-earths. [1] Current research on this topic focuses on extraction processes involving ionic liquids as basic extracting agents. In the aqueous phase, the rare-earth is coordinated by the anionic entities of the ionic liquid, forming an anionic complex. The large organic cation of the ionic liquid neutralizes the complex (ion-pair complex) and migrates the entity to an organic phase. The choice of these agents is solely based on the calculation of thermodynamical extraction parameters, whilst structural information about these compounds is rare or even non-existent. Our research focuses on obtaining structural information via crystallography on the above-mentioned molecules and relating the interactions between anion and cation to the stability of the complexes. A difference in stability between the anionic complex and cation can give a different extractability. Different rare-earth chloride salts were dissolved in an aqueous phase, containing ionic liquids with β-diketonate anions and 1-alkyl-3-methylimidazolium cations. After the extraction, crystals of the formed compounds are grown from the organic phase and measured. Current results show us that an intermolecular non-classical C-H ... O hydrogen bond is persistent across the different molecules, whilst small interactions between the cation side chain and halogens on the β-diketonate add extra stability to the crystal structure. Structures formed with 2-thenolytrifluoroactylacetonate anions have no intention to form side chain interactions, leaving the alkyl chain of the 1-alkyl-3-methylimidazolium in a void, whilst structures formed with hexafluoroacetylactonate have strong side chain interactions, which leads to a better packing. The different solubility of both compounds can be related to the different interactions and stability in the crystal structure.
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Rodenbücher, Christian, Yingzhen Chen, Klaus Wippermann et Carsten Korte. « Nanoscale Investigations of the Electric Double Layer in Protic Ionic Liquids ». ECS Meeting Abstracts MA2023-02, no 56 (22 décembre 2023) : 2718. http://dx.doi.org/10.1149/ma2023-02562718mtgabs.
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A hydrogen-based energy storage system will be the backbone of a future energy grid using renewable energies. Polymer electrolyte membrane fuel cells (PEMFCs) are a key element in this energy system as they convert chemical energy stored as hydrogen into electrical energy on demand. PEMFC systems, especially for automotive application, could be significantly improved by increasing the operation temperature above 100 °C. Protic ionic liquids are promising candidates as non-aqueous protic electrolytes for next-generation high-temperature polymer electrolyte membrane fuel cells. These fuel cells have a target operation temperature of 160 °C and allowing for a more efficient water and heat management compared to conventional Nafion®-based PEMFCs, which operate at temperatures below 80 °C [1]. In order to ensure a reliable and efficient operation an electrolyte with a high electrochemical performance and stability has to be selected. For this purpose, protic ionic liquids have been proposed and first fuel cell tests have shown promising results [2]. Hence, we aim on understanding the properties of this class of novel electrolytes on an atomistic level, which would allow designing suitable material combinations and predicting their properties for an efficient fuel cell operation. As ionic liquids are molten salts, which are liquid below 100 °C, their electrochemical properties differ significantly from those of aqueous solutions. Instead of a classical electric double layer, which can be described by the models provided by Helmholtz, Gouy-Chapman and Stern, the interface structure formed between the electrolyte and a charged electrode is governed by the interplay between coulomb interaction and steric effects between the (large) molecular ions [3]. In order to understand the formation of this double layer on a metallic electrode, we employ atomic force microscopy and infrared spectroscopy in combination with molecular dynamics simulations. Our results show that in the interface region between the prototype protic ionic liquid diethylmethylammonium triflate ([Dema][TfO]) and a Pt electrode, a dense layered structure consisting of alternating anion and cation layers is present, that extends several nanometres into the bulk of the electrolyte [4]. The composition and structure changes with applied potential due to a preferential attraction of anions or cations depending on the electrode charge. When water is added to the ionic liquid, the layered structure becomes distorted and water molecules appear near the electrode. Since the presence of water will also influence the relevant electrochemical processes such as the oxygen reduction reaction (ORR), the analysis of the double layer structure on an atomistic scale is necessary in order to understand the subtle interactions between the molecules in the electrolyte and to propose design routes for novel more efficient ionic liquid-based electrolytes. Wippermann, K.; Suo, Y.; Korte, C. Oxygen Reduction Reaction Kinetics on Pt in Mixtures of Proton-Conducting Ionic Liquids and Water: The Influence of Cation Acidity. J. Phys. Chem. C 2021, 125, 4423–4435, doi:10.1021/acs.jpcc.0c11374. Skorikova, G.; Rauber, D.; Aili, D.; Martin, S.; Li, Q.; Henkensmeier, D.; Hempelmann, R. Protic Ionic Liquids Immobilized in Phosphoric Acid-Doped Polybenzimidazole Matrix Enable Polymer Electrolyte Fuel Cell Operation at 200 °C. Journal of Membrane Science 2020, 608, 118188, doi:10.1016/j.memsci.2020.118188. Rodenbücher, C.; Wippermann, K.; Korte, C. Atomic Force Spectroscopy on Ionic Liquids. Applied Sciences 2019, 9, 2207, doi:10.3390/app9112207. Rodenbücher, C.; Chen, Y.; Wippermann, K.; Kowalski, P.M.; Giesen, M.; Mayer, D.; Hausen, F.; Korte, C. The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy. International Journal of Molecular Sciences 2021, 22, 12653, doi:10.3390/ijms222312653. Figure 1
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Hermida-Merino, Carolina, David Cabaleiro, Carlos Gracia-Fernández, Jesus Valcarcel, José Antonio Vázquez, Noelia Sanz, Martín Pérez-Rodríguez et al. « Ionogels Derived from Fluorinated Ionic Liquids to Enhance Aqueous Drug Solubility for Local Drug Administration ». Gels 8, no 9 (16 septembre 2022) : 594. http://dx.doi.org/10.3390/gels8090594.
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Gelatin is a popular biopolymer for biomedical applications due to its harmless impact with a negligible inflammatory response in the host organism. Gelatin interacts with soluble molecules in aqueous media as ionic counterparts such as ionic liquids (ILs) to be used as cosolvents to generate the so-called Ionogels. The perfluorinated IL (FIL), 1-ethyl-3-methylpyridinium perfluorobutanesulfonate, has been selected as co-hydrosolvent for fish gelatin due to its low cytotoxicity and hydrophobicity aprotic polar structure to improve the drug aqueous solubility. A series of FIL/water emulsions with different FIL content and their corresponding shark gelatin/FIL Ionogel has been designed to enhance the drug solubility whilst retaining the mechanical structure and their nanostructure was probed by simultaneous SAXS/WAXS, FTIR and Raman spectroscopy, DSC and rheological experiments. Likewise, the FIL assisted the solubility of the antitumoural Doxorubicin whilst retaining the performing mechanical properties of the drug delivery system network for the drug storage as well as the local administration by a syringe. In addition, the different controlled release mechanisms of two different antitumoral such as Doxorubicin and Mithramycin from two different Ionogels formulations were compared to previous gelatin hydrogels which proved the key structure correlation required to attain specific therapeutic dosages.
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Krämer, Günther, Florian Hausen et Roland Bennewitz. « Dynamic shear force microscopy of confined liquids at a gold electrode ». Faraday Discussions 199 (2017) : 299–309. http://dx.doi.org/10.1039/c6fd00237d.
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The confinement of liquids in nanometer-scale gaps can lead to changes in their viscous shear properties. For liquids of polar molecules, the charge state of the confining surfaces has a significant influence on the structure in the confined liquid. Here we report on the implementation of dynamic shear force microscopy in an electrochemical cell. Lateral oscillations of the tip of an atomic force microscope were magnetically activated at a frequency of about 50 kHz. The damping of the lateral tip oscillation was recorded as a function of the tip–sample distance and of the electrode potential at the surface of a Au(100) single crystal electrode. The influence of surface charges on the shear response of the nano-confined liquids was demonstrated for the ionic liquid [EMIM][NTf2] and for aqueous Na2SO4 solution.
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Gułajski, Łukasz, Marc Mauduit et Karol Grela. « Onium-tagged Ru complexes as universal catalysts for olefin metathesis reactions in various media ». Pure and Applied Chemistry 81, no 11 (31 octobre 2009) : 2001–12. http://dx.doi.org/10.1351/pac-con-08-10-13.
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Polar olefin metathesis catalysts bearing a pendant electron-withdrawing (EWG) onium group are reviewed. The presence of this group not only activates the catalysts electronically, but renders them more hydrophilic. Catalysts can, therefore, be efficiently used not only in traditional media such as methylene chloride and toluene, but also in technical-grade alcohols, alcohol–water mixtures, and in neat water. In addition, some onium-tagged catalysts can act as inisurfs (initiator + surfactant molecules), promoting metathesis under heterogeneous aqueous conditions. Finally, some of these catalysts can be used in ionic liquids. Various ring-closing-, cross- and enyne metathesis reactions were conducted with these catalysts.
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Nitta, Ayako, Takeshi Morita, Hiroyuki Ohno et Keiko Nishikawa. « Fluctuations and Mixing State of an Aqueous Solution of the Ionic Liquid Tetrabutylphosphonium Trifluoroacetate around the Critical Point ». Australian Journal of Chemistry 72, no 2 (2019) : 93. http://dx.doi.org/10.1071/ch18380.
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Aqueous solutions of ionic liquids have unique mixing states. Fluctuations are useful for understanding the inhomogeneity of the mixing states. In this study, an aqueous solution of tetrabutylphosphonium trifluoroacetate, ([P4,4,4,4]CF3COO), which exhibits a lower-critical-solution-temperature-type phase transition, was investigated. Focussing on the concentration and temperature range near the critical point, the fluctuations were evaluated by combining three kinds of experimentally obtained data: small-angle X-ray scattering intensity, partial molar volumes, and isothermal compressibility. Using Kirkwood–Buff integrals, individual density fluctuations of water and [P4,4,4,4]CF3COO were calculated, and these suggested that a large number of water molecules hydrated [P4,4,4,4]CF3COO ion pairs, and the hydrated ion pairs aggregated near the critical point. The relationship between the mesoscopic fluctuations and the macroscopic phase transition was clarified by drawing counter maps of the fluctuations in the phase diagrams.
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Xu, Wenzhuo, Xinpei Gao, Liqiang Zheng et Fei Lu. « Ionic-Liquid-Based Aqueous Two-Phase Systems Induced by Intra- and Intermolecular Hydrogen Bonds ». Molecules 27, no 16 (19 août 2022) : 5307. http://dx.doi.org/10.3390/molecules27165307.
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In recent years, aqueous two-phase systems (ATPSs) have been widely used in different fields and have become an increasingly attractive subject due to their application in the separation and purification of biomolecules. In this work, the aqueous phase behavior of ionic liquids (ILs) was modulated by changing the cis-trans structure of the anion in ILs. With the same tetra-butyl-phosphine as the cation, the cis-anion exhibited upper critical solution temperature (UCST) phenomena. In contrast, the trans-anion exhibited lower critical solution temperature (LCST) phenomena. The proposed mechanism shows that the main factors responsible for these phenomena include variations in the dissociation degree with temperature and the steric hindrance of the ILs. This phase behavior combines the chemical equilibrium in a solution with the microstructure of the molecule and is useful for constructing new chemical dynamic equilibria in ATPS. As an example of its application, aqueous solutions of both ILs can be used for the efficient separation and extraction of specific amino acids. The two ATPS systems reported in this work highlight a simple, effective, and environmentally friendly method for separating small biological molecules.
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Lebeau, Juliana, Thomas Petit, Mireille Fouillaud, Laurent Dufossé et Yanis Caro. « Aqueous Two-Phase System Extraction of Polyketide-Based Fungal Pigments Using Ammonium- or Imidazolium-Based Ionic Liquids for Detection Purpose : A Case Study ». Journal of Fungi 6, no 4 (18 décembre 2020) : 375. http://dx.doi.org/10.3390/jof6040375.
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Demand for microbial colorants is now becoming a competitive research topic for food, cosmetics and pharmaceutics industries. In most applications, the pigments of interest such as polyketide-based red pigments from fungal submerged cultures are extracted by conventional liquid–liquid extraction methods requiring large volumes of various organic solvents and time. To address this question from a different angle, we proposed, here, to investigate the use of three different aqueous two-phase extraction systems using either ammonium- or imidazolium-based ionic liquids. We applied these to four fermentation broths of Talaromyces albobiverticillius (deep red pigment producer), Emericella purpurea (red pigment producer), Paecilomyces marquandii (yellow pigment producer) and Trichoderma harzianum (yellow-brown pigment producer) to investigate their selective extraction abilities towards the detection of polyketide-based pigments. Our findings led us to conclude that (i) these alternative extraction systems using ionic liquids as greener extractant means worked well for this extraction of colored molecules from the fermentation broths of the filamentous fungi investigated here; (ii) tetrabutylammonium bromide, [N4444]Br-, showed the best pigment extraction ability, with a higher putative affinity for azaphilone red pigments; (iii) the back extraction and recovery of the fungal pigments from ionic liquid phases remained the limiting point of the method under our selected conditions for potential industrial applications. Nevertheless, these alternative extraction procedures appeared to be promising ways for the detection of polyketide-based colorants in the submerged cultures of filamentous fungi.
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Zhang, Minghao, Wen Xiao, Cunlin Zhang et Liangliang Zhang. « Terahertz Kerr Effect of Liquids ». Sensors 22, no 23 (2 décembre 2022) : 9424. http://dx.doi.org/10.3390/s22239424.
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In recent years, tremendous advancements have been made in various technologies such as far-infrared, low-frequency Raman, and two-dimensional (2D) Raman terahertz (THz) spectroscopies. A coherent method has emerged from numerous experimental and theoretical investigations of molecular dynamics in liquids by comparing linear and non-linear spectroscopic techniques. Intermolecular hydrogen bond vibration, molecular reorientation motion, and interaction between molecule/ionic solute and hydrogen bonds have been demonstrated to occur in the THz region, which are closely related to their physical/chemical properties and structural dynamics. However, precise probing of various modes of motion is difficult because of the complexity of the collective and cooperative motion of molecules and spectral overlap of related modes. With the development of THz science and technology, current state-of-the-art THz sources can generate pulsed electric fields with peak intensities of the order of microvolts per centimeter (MV/cm). Such strong fields enable the use of THz waves as the light source for non-linear polarization of the medium and in turn leads to the development of the emerging THz Kerr effect (TKE) technique. Many low-frequency molecular motions, such as the collective directional motion of molecules and cooperative motion under the constraint of weak intermolecular interactions, are resonantly excited by an intense THz electric field. Thus, the TKE technique provides an interesting prospect for investigating low-frequency dynamics of different media. In view of this, this paper first summarizes the research work on TKE spectroscopy by taking a solid material without low-frequency molecular motions as an example. Starting from the principle of TKE technology and its application in investigating the properties of solid matter, we have explored the low-frequency molecular dynamics of liquid water and aqueous solutions using TKE. Liquid water is a core of life and possesses many extraordinary physical and biochemical properties. The hydrogen bond network plays a crucial role in these properties and is the main reason for its various kinetic and thermodynamic properties, which differ from those of other liquids. However, the structure of the hydrogen bond network between water and solutes is not well known. Therefore, evaluating the hydrogen bond-related kinetic properties of liquid water is important.
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Nayl, AbdElAziz A., Wael A. A. Arafa, Ismail M. Ahmed, Ahmed I. Abd-Elhamid, Esmail M. El-Fakharany, Mohamed A. Abdelgawad, Sobhi M. Gomha et al. « Novel Pyridinium Based Ionic Liquid Promoter for Aqueous Knoevenagel Condensation : Green and Efficient Synthesis of New Derivatives with Their Anticancer Evaluation ». Molecules 27, no 9 (4 mai 2022) : 2940. http://dx.doi.org/10.3390/molecules27092940.
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Herein, a distinctive dihydroxy ionic liquid ([Py-2OH]OAc) was straightforwardly assembled from the sonication of pyridine with 2-chloropropane-1,3-diol by employing sodium acetate as an ion exchanger. The efficiency of the ([Py-2OH]OAc as a promoter for the sono-synthesis of a novel library of condensed products through DABCO-catalyzed Knoevenagel condensation process of adequate active cyclic methylenes and ninhydrin was next investigated using ultimate greener conditions. All of the reactions studied went cleanly and smoothly, and the resulting Knoevenagel condensation compounds were recovered in high yields without detecting the aldol intermediates in the end products. Compared to traditional strategies, the suggested approach has numerous advantages including mild reaction conditions with no by-products, eco-friendly solvent, outstanding performance in many green metrics, and usability in gram-scale synthesis. The reusability of the ionic liquid was also studied, with an overall retrieved yield of around 97% for seven consecutive runs without any substantial reduction in the performance. The novel obtained compounds were further assessed for their in vitro antitumor potential toward three human tumor cell lines: Colo-205 (colon cancer), MCF-7 (breast cancer), and A549 (lung cancer) by employing the MTT assay, and the findings were evaluated with the reference Doxorubicin. The results demonstrated that the majority of the developed products had potent activities at very low doses. Compounds comprising rhodanine (5) or chromane (12) moieties exhibited the most promising cytotoxic effects toward three cell lines, particularly rhodanine carboxylic acid derivative (5c), showing superior cytotoxic effects against the investigated cell lines compared to the reference drug. Furthermore, automated docking simulation studies were also performed to support the results obtained.
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Ers, Heigo, Liis Siinor et Piret Pikma. « The Puzzling Processes at Electrode | Ionic Liquid Interface ». ECS Meeting Abstracts MA2022-02, no 60 (9 octobre 2022) : 2533. http://dx.doi.org/10.1149/ma2022-02602533mtgabs.
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J.M. Lehn stated in his Nobel prize lecture in 1988 that supramolecular chemistry is the chemistry of the intermolecular bond, covering the structure and functions of entities formed by the association of two or more chemical species [1]. The adsorption of organic molecules is the net result of the interactions between the molecules and the two phases, the metal and the electrolyte, and the interactions between the latter two. To this day, the universal understanding that the adsorption of organic molecules results in the formation of an ordered monolayer is based on the phenomenon observed in mainly aqueous solutions. However, the conception might not be straightforwardly transferrable to the organic additive + ionic liquid | electrode interface. For example, the existence of an interfacial multilayer structure of pure IL ions in contrast with an aqueous electrolyte has been previously shown in both experimental and computational studies. Furthermore, it has been shown that in ILs, if the ions form rigid layers on the electrode, it is necessary to apply an overpotential for interfacial restructuring. Therefore, studying the adsorption of organic additives in ionic liquids (IL) should contribute to a better understanding of metal | IL interfaces. In the given presentation we overview the characteristics of solid-liquid interface characteristics of various additives from ionic liquid media at different electrodes. Cyclic voltammetry, electrochemical impedance spectroscopy and in situ scanning tunnelling microscopy measurements were conducted to characterize the electrochemical behavior of the self-assembled layers of 4,4’-bipyridine (4,4’-BP) and 2,2’-bipyridine (2,2’-BP) at the Sb(111) | x-BP+1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) interface [2-3]. The specific adsorption of iodide ions was studied at Bi(111), Cd(0001) and pyrolytic graphite electrodes [4-6]. All the experiments were carried out in a three-electrode electrochemical cell in a glovebox. The halide ions are surface active ions with specific adsorption behavior [4-6]. The strong specific adsorption of halide ions at single crystal electrodes, as well as other electrodes, is a complicated process due to the partial charge transfer between adsorbed ions and the solid electrode surface. The properties of the adsorption layer depend on the electrode potential and the concentration of the surface-active ions in an electrolyte. The theory that the adsorption of organic molecules results in SAM formation is mainly based on the results observed in aqueous solutions. However, these findings may not be as straightforwardly linkable to the organic additive + ionic liquid | electrode interface. The analysis of cyclic voltammetry and impedance results revealed that 2,2′-BP and 4,4′-BP indeed adsorb at the Sb(111) interface, forming a thin dielectric layer at the electrode surface, confirmed by in situ STM measurements, resulting in the differential capacitance values nearly two times lower compared to EMImBF4. Acknowledgments: This work was supported by the Estonian Research Council grant PSG249, and by the EU through the European Regional Development Fund under project TK141 (2014-2020.4.01.15-0011). References: [1] Lehn, J.-M., Angew. Chem. Int. Ed. Engl. 1988, 27 (1), 89–112. [2] Pikma et al., Electrochem. Commun. 2015, 61 (Supplement C), 61–65. [3] H. Ers et al., Electrochim. Acta 2022, 421, 140468. [4] H. Ers et al., J. Electroanal. Chem. 2021, 903, 115826. [5] L. Siinor et al., Electrochem. Commun. 2013, 35, 5–7. [6] L. Siinor et al., J. Electroanal. Chem. 2014, 719, 133–137.
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Persson, Ingmar, Josephina Werner, Olle Björneholm, Yina Salamanca Blanco, Önder Topel et Éva G. Bajnóczi. « Solution chemistry in the surface region of aqueous solutions ». Pure and Applied Chemistry 92, no 10 (25 octobre 2020) : 1553–61. http://dx.doi.org/10.1515/pac-2019-1106.
Texte intégralRésumé :
AbstractSolution chemistry is commonly regarded as the physical chemistry of reactions and chemical equilibria taking place in the bulk of a solvent, and between solutes in solution, and solids or gases in contact with the solution. Our knowledge about such reactions and equilibria in aqueous solution is very detailed such as their physico–chemical constants at varying temperature, pressure, ionic medium and strength. In this paper the solution chemistry in the surface region of aqueous solutions, down to ca. 10 Å below the water–air interface, will be discussed. In this region, the density and relative permittivity are significantly smaller than in the aqueous bulk strongly affecting the chemical behaviour of solutes. Surface sensitive X-ray spectroscopic methods have recently been applicable on liquids and solutions by use of liquid jets. This allows the investigation of the speciation of compounds present in the water–air interface and the surface region, a region hardly studied before. Speciation studies show overwhelmingly that neutral molecules are accumulated in the surface region, while charged species are depleted from it. It has been shown that the equilibria between aqueous bulk, surface region, solids and/or air are very fast allowing effective transport of chemicals over the aqueous surface region.
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Vicente, Filipa A., Luciana P. Malpiedi, Francisca A. e Silva, Adalberto Pessoa, João A. P. Coutinho et Sónia P. M. Ventura. « Design of novel aqueous micellar two-phase systems using ionic liquids as co-surfactants for the selective extraction of (bio)molecules ». Separation and Purification Technology 135 (octobre 2014) : 259–67. http://dx.doi.org/10.1016/j.seppur.2014.06.045.
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Robert, Tobias, Sean M. Mercer, Timothy J. Clark, Brian E. Mariampillai, Pascale Champagne, Michael F. Cunningham et Philip G. Jessop. « Nitrogen-containing polymers as potent ionogens for aqueous solutions of switchable ionic strength : application to separation of organic liquids and clay particles from water ». Green Chemistry 14, no 11 (2012) : 3053. http://dx.doi.org/10.1039/c2gc36074h.
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Ers, Heigo, Liis Siinor, Enn Lust et Piret Pikma. « The Adsorption of Bipyridine on Single-Crystal Electrodes from an Ionic Liquid Electrolyte ». ECS Meeting Abstracts MA2022-02, no 60 (9 octobre 2022) : 2485. http://dx.doi.org/10.1149/ma2022-02602485mtgabs.
Texte intégralRésumé :
The self-assembly of adsorbed molecules into structured adlayers on the electrode’s surface provides a straightforward way to modify the interface. Moreover, the formation and properties of the formed adlayers can be controlled by the applied potential, which offers fascinating prospects for the development of molecular switches1, thin film transistors2, and sensors3. Ionic liquids are a class of unique electrolytes, which properties differ notably from common aqueous or organic electrolytes. For example, due to good electrochemical stability and low vapour pressure of ionic liquids4, the adlayer formation process can be studied and the interfacial properties tuned in a significantly larger potential range. In the given presentation, we will focus on the adsorption of 4,4’-bipyridine (4,4’-BP) on single-crystal model electrodes from ionic liquid electrolyte. To gain insight into the process and formed structures, we have combined electrochemical impedance spectroscopy and in situ scanning tunnelling microscopy measurements with density functional theory calculations. The results show the formation of two distinct 4,4’-BP adlayers on the Sb(111) electrode on top of each other, visualized thanks to the occurrence of partial reductive desorption of 4,4’-BP5. In the case of the Cd(0001) surface, a similar reduction process was visible in the cyclic voltammetry and capacitance, potential dependences, although the formed 4,4’-BP adlayers were not visible with the in situ STM. Acknowledgments: This work was supported by the Estonian Research Council grant PSG249, and by the EU through the European Regional Development Fund under project TK141 (2014-2020.4.01.15-0011). References: Yasini, P. et al. Potential-Induced High-Conductance Transport Pathways through Single-Molecule Junctions. J. Am. Chem. Soc 141, 10109–10116 (2019). Casalini, S., Bortolotti, C. A., Leonardi, F. & Biscarini, F. Self-assembled monolayers in organic electronics. Chem. Soc. Rev. 46, 40–71 (2017). Singh, M., Kaur, N. & Comini, E. The role of self-assembled monolayers in electronic devices. J. Mater. Chem. C 8, 3938–3955 (2020). Galiński, M., Lewandowski, A. & Stepniak, I. Ionic liquids as electrolytes. Electrochim. Acta 51, 5567–5580 (2006). Ers, H., Siinor, L., Siimenson, C., Lust, E. & Pikma, P. Order beyond a monolayer: The story of two self-assembled 4,4′-bipyridine layers on the Sb(111) | ionic liquid interface. Electrochim. Acta 421, 140468 (2022).
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Chaudhary, Ankita, et Jitender M. Khurana. « Advances in the Synthesis of Xanthenes : An Overview ». Current Organic Synthesis 15, no 3 (27 avril 2018) : 341–69. http://dx.doi.org/10.2174/1570179414666171011162902.
Texte intégralRésumé :
Background: Xanthene is pharmacologically important oxygen containing heterocyclic moeity exhibiting an array of potent biological activities like antibacterial, antiviral, antiinflammatory, antitumor, antioxidant, antiplasmodial etc. Other useful applications of these heterocycles are as fluorescent materials for the visualization of biomolecules and in laser technology. Objective: This review gives an insight of the literature available on the methods for the construction of xanthene nucleus. This review article can be reasonably encouraging for those involved in the synthesis of molecules exhibiting a wide range of biological activities involving xanthene as central nucleus and would provide them assistance in developing new eco-friendly, efficient and economical viable methods. Conclusion: Owing to diverse applications of xanthenes, various synthetic methodologies have been developed, whether to construct this privileged scaffold. Many of the reported methods involve the use of various harsh catalysts/reagents that are not environmentally benign, produce a large amount of waste and need longer reaction times. The sustainable and diversity oriented synthesis of xanthene scaffold which incorporates Green Chemistry tools like multicomponent reaction approach, heterogeneous catalysts, alternate reaction media such as water, ionic liquids, polyethylene glycol etc. has also been developed.
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Zhu, Zhenghao, Ivan Popov, Alexei P. Sokolov et Stephen J. Paddison. « Mechanistic Insights into Proton Transport in Pure and Aqueous Phosphoric Acid ». ECS Meeting Abstracts MA2022-02, no 57 (9 octobre 2022) : 2178. http://dx.doi.org/10.1149/ma2022-02572178mtgabs.
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The transport of protons plays a key role in a variety of electrochemical processes and technologies. There are two major mechanisms underlying proton transport: the vehicular mechanism where a protonic defect moves with the aid of a molecular entity; and the ‘Grotthuss mechanism’ where a proton diffuses by being transferred between ‘chains’ of host molecules via elementary reactions within the hydrogen bond networks. The latter is regarded as the most efficient proton conductivity mechanism. Although Grotthuss proposed this concept more than 200 years ago, only indirect experimental evidence of the mechanism has thus far been reported. Recently, we observed the first direct experimental observation of proton transfer between the molecules in pure and 85% aqueous phosphoric acid by employing dielectric spectroscopy, and quasi-elastic neutron scattering (QENS). Complementary to these experiments, ab initio molecular dynamics (AIMD) simulations were performed to gain molecular insight into the underlying mechanisms of proton transport allowing for the breaking and forming of covalent bonds since it calculates the forces from electronic structure methods ‘on the fly’. We calculated the self-intermediate scattering function of the protons, indicating three processes at high Q range consisting of two fast Q-independent processes and one slow Q-dependent process, which are in good agreement with QENS results. Also, the self-part of van Hove function of the protons for the fast characteristic time shows surprisingly short proton jumps of only ~0.5 - 0.7 Å confirmed by analysis of an individual proton trajectory. Furthermore, AIMD demonstrates that proton hopping plays an essential role in the long-range proton diffusion through the breaking and forming of hydrogen bonds. Our analysis confirmed the strong proton-proton correlations in these proton jumps. However, this correlated proton transport unexpectedly leads to a decrease of conductivity in these systems. Based on these results, we propose that the expected Grotthuss-like enhancement mechanism of conductivity cannot be realized in bulk liquids where ionic correlations always reduce conductivity, most likely because of the requirement for the momentum conservation. Our findings will propel the design of electrochemical materials with proton transfers involved in charge transport for achieving high proton conductivity in electrochemical applications including fuel cells.
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Hefter, Glenn, et Richard Buchner. « Dielectric relaxation spectroscopy : an old-but-new technique for the investigation of electrolyte solutions ». Pure and Applied Chemistry 92, no 10 (25 octobre 2020) : 1595–609. http://dx.doi.org/10.1515/pac-2019-1011.
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AbstractThe use of dielectric relaxation spectroscopy (DRS) for studying electrolyte solutions is reviewed, focussing on the authors’ investigations over the last three decades. It is shown that this often-overlooked technique provides powerful insights into the nature of ion-ion and ion-solvent interactions. DRS is revealed to be particularly useful for detection of weak ion association and, due to its unique ability to detect solvent-separated species, the quantitation of ion pairing. It is demonstrated that DRS correctly determines chemical speciation for ion-paired systems where major spectroscopic techniques (NMR, Raman, UV-vis) fail. DRS also provides important insights into ion solvation. In aqueous solutions, it has been used to build up a coherent set of ‘effective’ hydration numbers for ions based on the dynamics of proximate water molecules, and has a unique ability to detect ‘slow’ water resulting from hydrophilic and hydrophobic hydration of solutes. DRS has been especially useful for characterising the behaviour of ionic liquids (ILs), e.g. showing they possess rather low dielectric constants and, surprisingly, contain no significant concentrations of ion pairs. Neat ILs and their mixtures with molecular solvents are shown by ultra-broadband DRS to exhibit extremely complicated behaviour especially at frequencies in the THz region.
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Kashpur, V., O. Khorunzhaya et D. Pesina. « Dielectrometry of hydration of fl avin mononucleotide and DNA ». RADIOFIZIKA I ELEKTRONIKA 26, no 3 (2021) : 46–53. http://dx.doi.org/10.15407/rej2021.03.046.
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Subject and Purpose. The elucidation of the molecular mechanisms of action of biomolecules is necessary for the development of state-of-the-art means of diagnosing and treatment. Dielectric studies in the millimeter wave range are effective for puzzling out the nature of the interaction of biomolecules with a surrounding aqueous solvent. Flavin mononucleotide (FMN), which can kill microorganisms and destroy cancer cells, is of particular interest. The aim of the work is to recognize hydration effects (changes in the state of water molecules) in FMN solutions. Methods and Methodology. The complex dielectric permittivity (CDP) is measured in the EHF range. Knowing the difference between the CDP of FMN solution and the CDP of water we find the difference, D es , between the effective dielectric permittivities in terms of the Debye theory of polar liquids. Since the relaxation time of dipoles of bound water is one or two orders of magnitude longer than that of free water, the amount of the difference D es characterizes the hydration of biomolecules. At low concentrations, this difference is proportional to the number of bound water molecules. Results. It has been shown that approximately18 water molecules are bound to the FMN molecule. Groups of atoms as the most probable hydration centers (primarily due to the hydrogen bonds) have been indicated. As the pH decreases, the number of water molecules bound to the Flavin mononucleotide increases to 21. The study of the FMN–DNA solution has shown that one nucleotide accounts for 25–26 bound water molecules in total. However, composing hydration numbers assumes a quantity of components less than 20. An assumption is made that the additional components are due to the cooperative nature of the hydration, leading to the fact that even if some solvent molecules do not come into a direct contact with hydration centers, they are under the influence of biomolecules all the same. Conclusion. Extremely-high-frequency dielectrometry is an effective method of research into the interaction of biomolecules with a water-ionic solvent. A FMN hydration model has been proposed, which indicates probable hydration centers and tells a measure of their effect on the solvent. It has been found that the FMN with DNA interaction increases the number of bound water molecules per one nucleotide of the DNA. The obtained results have been compared to the existing models of the DNA with FMN interaction.
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Roy, Dipankar, et Andriy Kovalenko. « Multiscale Methods Framework with the 3D-RISM-KH Molecular Solvation Theory for Supramolecular Structures, Nanomaterials, and Biomolecules : Where Are We Going ? » Thermo 3, no 3 (2 juillet 2023) : 375–95. http://dx.doi.org/10.3390/thermo3030023.
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3D-RISM-KH molecular solvation theory based on statistical mechanics has been an engine of the multiscale methods framework, which also includes molecular simulation techniques. Its applications range from the solvation energy of small molecules to the phase behavior of polymers and biomolecules. Molecular solvation theory predicts and explains the molecular mechanisms and functioning of a variety of chemical and biomolecular systems. This includes the self-assembly and conformational stability of synthetic organic rosette nanotubes (RNTs), the aggregation of peptides and proteins related to neurodegeneration, the binding of ligands to proteins, and the solvation properties of biomolecules related to their functions. The replica RISM-KH-VM molecular solvation theory predicts and explains the structure, thermodynamics, and electrochemistry of electrolyte solutions sorbed in nanoporous carbon supercapacitor electrodes, and is part of recent research and development efforts. A new quasidynamics protocol couples multiple time step molecular dynamics (MTS-MD) stabilized with an optimized isokinetic Nosé–Hoover (OIN) thermostat driven by 3D-RISM-KH mean solvation forces at gigantic outer time steps of picoseconds, which are extrapolated forward at short inner time steps of femtoseconds with generalized solvation force extrapolation (GSFE). The OIN/3D-RISM-KH/GSFE quasidynamics is implemented in the Amber Molecular Dynamics package. It is validated on miniprotein 1L2Y and protein G in ambient aqueous solution, and shows the rate of sampling 150 times faster than in standard MD simulations on these biomolecules in explicit water. The self-consistent field version of Kohn–Sham DFT in 3D-RISM-KH mean solvation forces is implemented in the Amsterdam Density Functional (ADF) package. Its applications range from solvation thermochemistry, conformational equilibria, and photochemistry to activation barriers of different nanosystems in solutions and ionic liquids.
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Huang, Qiang. « (Invited) Chemistry Effects on the Electrodeposition of Re, Co, and Alloys ». ECS Meeting Abstracts MA2022-02, no 30 (9 octobre 2022) : 1083. http://dx.doi.org/10.1149/ma2022-02301083mtgabs.
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Electrodeposition has been adopted in various metallization processes. It allows conformal and super-conformal deposition on curved and recessed substrates, enables the fabrication of metals and alloys with well controlled composition, impurity, and grain structure, and provides fast growth rate, high throughput, and low cost of ownership. Organic additives have been used in electrolytes to tune not only the growth behavior, but also the impurity and grain structure of the deposited material. The most well-known cases are those used for magnetic alloy plating[1,2] in storage and MEMS industry and for damascene copper plating[3,4] in microelectronic industry. On the other hand, the electrolyte itself has largely remained aqueous for most cases. Organic solvents, room temperature ionic liquids, and deep eutectic systems have been widely studied with, however, relatively limited success in large scale adoption. The first part of this talk will introduce some studies on the electrodeposition of Cobalt as an alternative metal for semiconductor interconnect applications. Organic additives that tailor the deposition rate of cobalt are used to enable the Co filling in sub-micron structures. The effect of such additives on the impurity incorporation and film grain structure will be discussed. The second part of the talk will discuss some recent studies on the electrodeposition from “water-in-salt” electrolytes, where the hydration of a super high concentration of supporting salt depletes the free water molecules in the aqueous solution, thus limiting the hydrogen evolution reaction. The discussion will be in a context of Re and ReCo alloy deposition for superconducting connector applications for quantum devices. REFERENCES T. Osaka, M. Takai, K. Hayashi, K. Ohashi, M. Saito, and K. Yamada, A soft magnetic CoNiFe film with high saturation magnetic flux density and low coercivity, Nature, 1998, 392(6678), 796. E.I. Cooper, C. Bonhôte, J. Heidmann, Y. Hsu, P. Kern, J.W. Lam, M. Ramasubramanian, N. Robertson, L.T. Romankiw, and H. Xu, Recent developments in high-moment electroplated materials for recording heads, IBM Journal of Research and Development, 2005, 49(1), 103. P. Andricacos, C. Uzoh, J. Dukovic, J. Horkans, and H. Deligianni, Damascene copper electroplating for chip interconnections, IBM Journal of Research and Development, 1998, 42(5), 567. T.P. Moffat, J.E. Bonevich, W.H. Huber, A. Stanishevsky, D.R. Kelly, G.R. Stafford, and D. Josell, Superconformal Electrodeposition of Copper in 500–90 nm Features, Journal of The Electrochemical Society, 2000, 147, 4524.
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Khoma, Ruslan, Sergey Vodzinskii et Danyil Klimov. « IMPREGNATED ACTIVATED CARBON MATERIALS FOR RESPIRATORY PURPOSE. CHEMISORPTION OF SULFUR DIOXIDE ». Ukrainian Chemistry Journal 89, no 10 (24 novembre 2023) : 124–44. http://dx.doi.org/10.33609/2708-129x.89.10.2023.124-144.
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The review is devoted to the use of impregnated activated carbon materials as chemisorbents of sulfur (IV) oxide. General methods for obtaining ordinary activated carbon, preparation of raw materials, their chemical activation with alkalis and acids followed by heat treatment (carbonization) in an inert environment or in the presence of a gaseous oxidizer, the role of acid-base and redox catalysts in this process are considered. The influence of the chemical composition of the activated carbon surface, the presence of functional groups, and their acid-base properties, as well as the products of surface reactions on the peculiarities of sulfur (IV) oxide adsorption is analyzed from the point of view of SO2 removal efficiency and the possibility of SO2 regeneration. An important role in these processes is played by the pore size, the possibility of co-adsorption of water, and the presence of an oxidant. The nature of adsorbent-adsorbate interactions on the surface of activated carbon, their energy, in particular, the contribution of so-called "physical" adsorption, van der Waals forces, hydrogen bonding, and the influence of surface functional groups are discussed. The activation of carbon raw materials with nitrogen-containing compounds leads to the N-doping of the surface, which increases the efficiency of SO2 adsorption, facilitating not only van der Waals and electrostatic interactions, but also S←N binding. The influence of oxygen and oxygen-containing functional groups on SO2 adsorption is also discussed. To obtain impregnated activated carbon for SO2 absorption, the original activated carbon of the required quality is impregnated with solutions of inorganic and organic compounds that remain on the inner surface of the activated carbon after drying. Impregnation blocks partly the porosity of activated carbon, but makes it more capable of chemical adsorption. Chemisorption, in which certain chemical bonds are formed between the surface of the activated carbon and the compound being adsorbed, is more selective than physical adsorption, where the size of molecules is critical for an effective capture process. It can be noted that unlike inorganic alkalis, which spoil the porous structure of activated carbon, treatment with a solution of ammonia or organic N-containing bases promotes SO2 absorption. A special place in gas purification is occupied by activated carbon impregnated with ionic liquids, non-aqueous solvents being used for impregnation. A separate issue of the chemisorption of sulfur (IV) oxide by samples of impregnated activated carbon based on d-metals will be discussed in detail below.
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Lu, Xuejun, María C. Gutiérrez, M. Luisa Ferrer, Xuejun Lu et Jian Liu. « “Tri-Solvent-in-Salt” Electrolytes for High-Performance Supercapacitors ». ECS Meeting Abstracts MA2022-01, no 35 (7 juillet 2022) : 1412. http://dx.doi.org/10.1149/ma2022-01351412mtgabs.
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Electrolytes chemistry for high-performance supercapacitors (SCs) has been addressed recently, where solvents included in electrolyte composition dissolving or mixing the electrochemically active salts or ILs have been typically seen as a mere medium.[1] Specifically, attention regarding the achievement of high-performacne SCs has also been paid to, e.g., water-in-salt (WIS), solvent-in-salt (SIS), and bi-solvent-in-salt (BSIS) electrolytes, demonstrating that solvent molecules may indeed play a more active role.[2 - 4] In this presentation, we will talk about the design of a tri-solvent-in-salt (TSIS) electrolyte where every solvent contributed (with an IL, i.e., EMIMBF4) to the formation of an electrochemically active hydrogen bond (HB) complex structure. Raman and NMR spectroscopies, as well as molecular dynamic (MD) simulations, helped elucidate the ratio among all compounds (e.g., solvents and IL) in the HB complex structure that best works as an electrolyte. For instance, the eutectic mixture of H2O and dimethylsulfoxide (DMSO) in a 2 to 1 molar ratio primary HB complex structures with mixed EMIMBF4 offers a low melting point and low flammability, then add acetonitrile (CH3CN) in different molar ratios providing an improvement of the rate capability to the resulting electrolyte. As compared to other electrolytes, the TSIS electrolyte composed in a molality of 5.8 m (TSIS-5.8) showed the cost efficiency and exhibited a low self-extinction rate. Moreover, SCs operating with TSIS-5.8, at -70 °C and up to 2.7 V provided energy densities of ca. 49 and 18 Wh kg-1, respectively, power densities of 10,000 and 17,000 W kg-1, the capacitance retention of ca. 82% after 15,000 cycles at 4 A g-1 and a self-discharge as low as 22%. The use of ternary solvent mixtures combining different solvents in the proper molar ratios opens up an easy and low-cost path to design many new electrolytes in terms of non-flammability, non-toxicity, high electrical conductivity, and wide electrochemical stability window (ESW). Forthcoming research could use the knowledge provided by this work in terms of ions solvation and transport in TSIS electrolytes and explore the interfacial interactions between electrolyte and electrode material to determine their respective relevance in the performance of SCs. Keywords: tri-solvent-in-salt (TSIS), hydrogen bond, eutectic mixtures, supercapacitors Reference ： [1] F. Béguin, et al. Carbons and electrolytes for advanced supercapacitors. Adv. Mater., 26 (2014), 2219-2251. [2] Q. Dou, et al. Safe and high-rate supercapacitors based on an ‘‘Acetonitrile/Water in Salt’’ hybrid electrolyte. Energy Environ. Sci, 11 (2018), 3212-3219. [3] X. Lu, et al. Aqueous-Eutectic-in-Salt Electrolytes for High-Energy-Density Supercapacitors with an Operational Temperature Window of 100 °C, from −35 to +65 °C. ACS Appl. Mater. Interfaces 2020, 12, 26, 29181–29193. [4] X. Lu, et al. Aqueous Co-Solvent in Zwitterionic-based Protic Ionic Liquids as Electrolytes in 2.0 V Supercapacitors. ChemSusChem 2020, 13, 5983. [5] X. Lu, et al. EMIMBF4 in ternary liquid mixtures of water, dimethyl sulfoxide and acetonitrile as “tri-solvent-in-salt” electrolytes for high-performance supercapacitors operating at -70 °C. Energy Storage Mater., 40, (2021), 368-385.
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Jethwa, Rajesh B., Angelina Castro-Trujillo, Julia Valentin, Lakshman V. Kilari, Fernando Solorio-Soto, Stefan Stadlbauer et Stefan A. Freunberger. « Organic Bulk Liquid Redox Active Materials for Redox Flow Batteries ». ECS Meeting Abstracts MA2023-02, no 4 (22 décembre 2023) : 534. http://dx.doi.org/10.1149/ma2023-024534mtgabs.
Texte intégralRésumé :
Redox flow batteries (RFBs) are one potential solution to grid-level electrical energy storage (EES) benefiting from a decoupled power and capacity scaling.1–3 High durability, long-calendar life, high efficiency EES with a low cost and fast response time is needed1,4 for the transition from fossil fuels to renewable sources.3 However, the low energy density3,5,6 and high capital costs5,6 of current systems preclude wide-scale deployment of this technology. In recent years, several new RFB chemistries have been explored to address these concerns.1,2,7 However, a high solubility for a high volumetric energy density remains a troublesome target.1 It is, therefore, no surprise that one growing trend in this regard is the design of redox active liquids (RALs).8–13 RALs provide a means of dramatically increasing the volumetric energy density of RFBs through either miscibility with typical supporting electrolytes, or by acting as both solvent and electrolyte themselves.9,12 In this work, we investigate a series of RALs that offer a similar theoretical energy density to conventional intercalation materials. A combination of computational and experimental techniques was employed herein for both molecular design and explanation of the physio-chemical phenomena. The candidate compounds were initially screened via electrochemical techniques to identify their electrochemical reversibility and stability. Exploration of the bulk properties was then carried out before system-level characterisation was undertaken. In tandem, the electrochemical and chemical stability of the samples was also investigated through the typical routes (NMR, EPR, UV-Vis). These systems show much promise for organic, tuneable electrical energy storage. Cao, J., Tian, J., Xu, J. & Wang, Y. Organic Flow Batteries: Recent Progress and Perspectives. Energy and Fuels 34, 13384–13411 (2020). Ding, Y., Zhang, C., Zhang, L., Zhou, Y. & Yu, G. Molecular engineering of organic electroactive materials for redox flow batteries. Chem. Soc. Rev. 47, 69–103 (2018). Alotto, P., Guarnieri, M. & Moro, F. Redox flow batteries for the storage of renewable energy: A review. Renew. Sustain. Energy Rev. 29, 325–335 (2014). Weber, A. Z. et al. Redox flow batteries: A review. J. Appl. Electrochem. 41, 1137–1164 (2011). Potash, R. A., McKone, J. R., Conte, S. & Abruña, H. D. On the Benefits of a Symmetric Redox Flow Battery. J. Electrochem. Soc. 163, A338–A344 (2016). Wang, W. et al. Recent progress in redox flow battery research and development. Adv. Funct. Mater. 23, 970–986 (2013). Li, Z., Jiang, T., Ali, M., Wu, C. & Chen, W. Recent Progress in Organic Species for Redox Flow Batteries. Energy Storage Mater. 50, 105–138 (2022). Shimizu, A. et al. Liquid Quinones for Solvent-Free Redox Flow Batteries. Adv. Mater. 29, 1606592 (2017). Robertson, L., Udin, M. A., Shlrob, I. A., Moore, J. S. & Zhang, L. Liquid Redoxmers for Nonaqueous Redox Flow Batteries. ChemSusChem e202300043 (2023) doi:10.1002/cssc.202300043. Chen, N., Chen, D., Wu, J., Lai, Y. & Chen, D. Polyethylene glycol modified tetrathiafulvalene for high energy density non-aqueous catholyte of hybrid redox flow batteries. Chem. Eng. J. 462, 141996 (2023). Smith, L. O. & Crittenden, D. L. Acid‐Base Chemistry Provides a Simple and Cost‐Effective Route to New Redox‐Active Ionic Liquids. Chem. – An Asian J. 18, e202201296 (2023). Zhao, Y. et al. TEMPO allegro: liquid catholyte redoxmers for nonaqueous redox flow batteries. J. Mater. Chem. A 9, 16769–16775 (2021). Huang, J. et al. Liquid Catholyte Molecules for Nonaqueous Redox Flow Batteries. Adv. Energy Mater. 5, 1401782 (2015).
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Magnussen, Olaf M. « (Invited) Atomic-Scale Aspects of Nucleation and Growth at Liquid-Liquid Interfaces ». ECS Meeting Abstracts MA2022-01, no 23 (7 juillet 2022) : 1152. http://dx.doi.org/10.1149/ma2022-01231152mtgabs.
Texte intégralRésumé :
Interfaces between liquid metals and liquid electrolytes, in particular the liquid Hg - electrolyte interface, have played a key role in the development of the theory of the electrical double layer and electrochemical adsorption. More recently, liquid-liquid interfaces have regained interest in the field of material synthesis. Unlike solid interfaces, where strain and stress, heterogeneities, and defects strongly influence growth processes, fluid systems provide soft, defect- and stress-free interfaces. In addition, the growth process profits from the high mobility of atoms, molecules, and particles in both liquids, which allows growth from both sides of the phase boundary. A large variety of metallic and non-metallic nanomaterials has been prepared via electrochemical and electroless deposition at such liquid-liquid interfaces. As demonstrated by Maldonado and coworkers, electrodeposition at liquid metal electrodes even allows the growth of nanostructured crystalline semiconductors via a simple one-step, room-temperature electrochemical process [1]. Understanding of the fundamental processes in nucleation and growth at liquid-liquid interfaces is hampered by difficulties in studying these interfaces experimentally on the atomic scale. Most surface-sensitive techniques, especially also scanning probe microscopy methods, cannot access these fluidic phase boundaries. For this reason, the majority of studies relies on electrochemical measurements, optical microscopy, and ex situ investigation of the deposit and thus provide little insight on the initial steps of the growth process. We have shown in the past that hard X-ray scattering methods, such as X-ray reflectivity (XRR) and grazing incidence X-ray scattering (GIXS), are unique tools for determining the atomic liquid-liquid interface structure. In this talk, we present case studies of electrochemically induced growth at liquid interfaces from the first monolayer up to several ten nanometer thick films. The first part discusses the growth of ionic compounds, using lead halides on Hg electrodes as an example. In PbBr2 containing NaF we observed previously growth of a PbBrF layer by operando X-ray scattering. This growth exhibited a complex nucleation and growth behavior, involving a crystalline precursor layer prior to 3D crystal growth [2]. The well-defined subnanometer thick precursor layer provided a template for the subsequent quasi-epitaxial growth of oriented 3D crystallites. Detailed studies on the potential-dependent nucleation and growth kinetics revealed with increasing overpotential a crossover from a low surface density film of large crystals to a compact PbBrF deposit with a saturation thickness of 25 nm [3,4]. In addition, growth on the liquid substrate was found to involve micromechanical effects, such as crystal reorientation and film breakup during dissolution. More recently, we extended these studies to growth in solutions containing only one type of halide anion (Br, Cl, or F). Also here, the formation of precursor layers was observed, indicating that this growth behavior is a general phenomenon. In the second part, joint X-ray scattering studies with Maldonado and coworkers on the electrochemical liquid-liquid-solid deposition of semiconductors from aqueous electrolyte are presented, focusing on Ge electrodeposition on Hg and HgxIn1-x alloy electrodes [5]. We provide evidence for the adsorption of GeO3 - anions on the liquid metal surface and the formation of a crystalline GeO2 adlayer at the positive end of the double layer region. Ge electrodeposition results in nanocrystals, which are separated from the Hg electrode by a water cushion. Furthermore, pronounced Hg surface segregation is found in HgxIn1-x, which protects the electrode surface from oxidation in the potential regime of Ge deposition. [1] Carim, A. I., Collins, S. M., Foley, J. M. & Maldonado, J. Am. Chem. Soc. 133, 13292 (2011) [2] A. Elsen, S. Festersen, B. Runge, C.T. Koops, B. M. Ocko, M. Deutsch, O. Seeck, B. M. Murphy, O. M. Magnussen, Proc. Nat. Acad. Sci., 110, 6663 (2013) [3] B.M. Murphy, S. Festersen, O.M. Magnussen, Nanoscale, 8, 13859 (2016) [4] S. Festersen, B. Runge, C. Koops, F. Bertram, B.M. Ocko, M. Deutsch, B.M. Murphy, O.M. Magnussen, Langmuir, 36, 10905 (2020) [5] D. Pattadar, Q. Cheek, A. Satori, Y. Zhao, P.R. Giri, B. Murphy, O.M. Magnussen, S. Maldonado, Cryst. Growth Des., 21, 1645 (2021)
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« Exploration of Solvation Consequences of Some Biologically Potent Molecules in Aqueous Ionic Liquid Solutions with the Manifestation of Molecular Interactions ». Journal of Chemical, Biological and physical sciences 11, no 1 (24 janvier 2021). http://dx.doi.org/10.24214/jcbps.a.11.1.09114.
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Kurnik, Isabelle, Natália D’Angelo, Priscila Gava Mazzola, Marlus Chorilli, Daniel Kamei, Jorge F. B. Pereira, António A. Vicente et André Lopes. « Polymeric micelles using cholinium-based ionic liquids for the encapsulation and drug release of hydrophobic molecules ». Biomaterials Science, 2021. http://dx.doi.org/10.1039/d0bm01884h.
Texte intégralRésumé :
We generated stable amphiphilic copolymer-based polymeric micelles (PMs) with temperature-responsive properties utilizing Pluronic® L35 and a variety of ionic liquids (ILs) to generate different aqueous two-phase micellar systems (ATPMSs). The...
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Singh, Sushma, Sidhant Yadav, Minakshi Yadav et Rashmi Pundeer. « Green Synthesis of Pyrazoles : Recent Developments in Aqueous Methods ». SynOpen, 5 juillet 2023. http://dx.doi.org/10.1055/a-2123-8102.
Texte intégralRésumé :
Abstract Organic syntheses by adopting green protocols such as sonochemical procedures, microwave technologies, solvent-free conditions, green solvent, heterogeneous catalysis particularly nanocatalysts, ionic liquids have replaced the traditional procedures due to concerns pertaining especially to environment. The heterocycle, pyrazole, due to its multifaceted applications has been the cyanosure of the chemists and therefore various synthetic approaches have been developed to synthesize the pyrazole containing molecules. In the present compilation, we have summarized the recent water-based research work on the synthesis of pyrazoles. Key words: Green chemistry, environment friendly, water based synthesis, pyrazoles
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XIAO, TAO, JINLIN YANG, BAO ZHANG, JIAWEN WU, JINLIANG LI, WENJIE MAI et Hong Jin Fan. « All‐Round Ionic Liquids for Shuttle‐Free Zinc‐Iodine Battery ». Angewandte Chemie International Edition, 5 janvier 2024. http://dx.doi.org/10.1002/anie.202318470.
Texte intégralRésumé :
The practical implementation of aqueous zinc‐iodine batteries (ZIBs) is hindered by the rampant Zn dendrites growth, parasite corrosion, and polyiodide shuttling. In this work, ionic liquid EMIM[OAc] is employed as an all‐round solution to mitigate challenges on both the Zn anode and the iodine cathode side. First, the EMIM+ embedded lean‐water inner Helmholtz plane (IHP) and inert solvation sheath modulated by OAc‐ effectively repels H2O molecules away from the Zn anode surface. The preferential adsorption of EMIM+ on Zn metal facilitates uniform Zn nucleation via a steric hindrance effect. Second, EMIM+ can reduce the polyiodide shuttling by hindering the iodine dissolution and forming an EMIM+–I3– dominated phase. These effects holistically enhance the cycle life, which is manifested by both Zn||Zn symmetric cells and Zn‐I2 full cells. ZIBs with EAc deliver a capacity decay rate of merely 0.01 ‰ per cycle after over 18,000 cycles at 4 A g‐1, and lower self‐discharge and better calendar life than the ZIBs without ionic liquid EAc additive.
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XIAO, TAO, JINLIN YANG, BAO ZHANG, JIAWEN WU, JINLIANG LI, WENJIE MAI et Hong Jin Fan. « All‐Round Ionic Liquids for Shuttle‐Free Zinc‐Iodine Battery ». Angewandte Chemie, 5 janvier 2024. http://dx.doi.org/10.1002/ange.202318470.
Texte intégralRésumé :
The practical implementation of aqueous zinc‐iodine batteries (ZIBs) is hindered by the rampant Zn dendrites growth, parasite corrosion, and polyiodide shuttling. In this work, ionic liquid EMIM[OAc] is employed as an all‐round solution to mitigate challenges on both the Zn anode and the iodine cathode side. First, the EMIM+ embedded lean‐water inner Helmholtz plane (IHP) and inert solvation sheath modulated by OAc‐ effectively repels H2O molecules away from the Zn anode surface. The preferential adsorption of EMIM+ on Zn metal facilitates uniform Zn nucleation via a steric hindrance effect. Second, EMIM+ can reduce the polyiodide shuttling by hindering the iodine dissolution and forming an EMIM+–I3– dominated phase. These effects holistically enhance the cycle life, which is manifested by both Zn||Zn symmetric cells and Zn‐I2 full cells. ZIBs with EAc deliver a capacity decay rate of merely 0.01 ‰ per cycle after over 18,000 cycles at 4 A g‐1, and lower self‐discharge and better calendar life than the ZIBs without ionic liquid EAc additive.
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Popov, Ivan, Zhenghao Zhu, Amanda R. Young-Gonzales, Robert L. Sacci, Eugene Mamontov, Catalin Gainaru, Stephen J. Paddison et Alexei P. Sokolov. « Search for a Grotthuss mechanism through the observation of proton transfer ». Communications Chemistry 6, no 1 (22 avril 2023). http://dx.doi.org/10.1038/s42004-023-00878-6.
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AbstractThe transport of protons is critical in a variety of bio- and electro-chemical processes and technologies. The Grotthuss mechanism is considered to be the most efficient proton transport mechanism, generally implying a transfer of protons between ‘chains’ of host molecules via elementary reactions within the hydrogen bonds. Although Grotthuss proposed this concept more than 200 years ago, only indirect experimental evidence of the mechanism has been observed. Here we report the first experimental observation of proton transfer between the molecules in pure and 85% aqueous phosphoric acid. Employing dielectric spectroscopy, quasielastic neutron, and light scattering, and ab initio molecular dynamic simulations we determined that protons move by surprisingly short jumps of only ~0.5–0.7 Å, much smaller than the typical ion jump length in ionic liquids. Our analysis confirms the existence of correlations in these proton jumps. However, these correlations actually reduce the conductivity, in contrast to a desirable enhancement, as is usually assumed by a Grotthuss mechanism. Furthermore, our analysis suggests that the expected Grotthuss-like enhancement of conductivity cannot be realized in bulk liquids where ionic correlations always decrease conductivity.
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Yankov, Dragomir. « Aqueous two-phase systems as a tool for bioseparation – emphasis on organic acids ». Physical Sciences Reviews 5, no 9 (21 avril 2020). http://dx.doi.org/10.1515/psr-2018-0067.
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AbstractAqueous two-phase systems (ATPS) are universally recognized as an excellent alternative to the conventional separation techniques in the biotechnology, because of their undoubted advantages such as mild and biocompatible conditions, high water content, low interfacial tension, ease of process integration and scale up, etc. The formation of ATPS is due to the incompatibility of two polymers in a common solution. Other types of ATPS are formed by polymer/salt, ionic and/or non-ionic surfactants, inorganic salt/short-chain alcohols, and based on room temperature ionic liquids. ATPS are successfully used (even in large scale) for cells, enzyme and protein separation, while their application for recovery of small molecules such as organic acids, antibiotics, alcohols is more complicated as they are usually hydrophilic and tend to distribute evenly between the phases. The purpose of this paper is to overview and summarize the efforts made for the application of different types of ATPS for the separation of organic acids.
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Wang, Yicong, Shanshan Wang et Leilei Liu. « Recovery of natural active molecules using aqueous two-phase systems comprising of ionic liquids/deep eutectic solvents ». Green Chemical Engineering, juillet 2021. http://dx.doi.org/10.1016/j.gce.2021.07.007.
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Pahovnik, David, Ema Žagar, Jiří Vohlídal et Majda Žigon. « Effect of cations on polyaniline morphology ». Chemical Papers 67, no 8 (1 janvier 2013). http://dx.doi.org/10.2478/s11696-013-0352-6.
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AbstractNanostructured polyanilines of different morphologies were prepared by chemical polymerization of aniline with ammonium peroxodisulfate in aqueous HCl using various inorganic and organic chlorides as additives with the aim to determine the effect of cations of the added electrolyte on the morphology, spectroscopic characteristics, and conductivity of formed polyanilines. Chlorides of basic metals: NaCl and CaCl2 did not show any significant effect while AlCl3 and organic electrolytes were found to influence the morphology of polyanilines. The effect of organic-electrolyte additives, which actually are ionic liquids, is explained by the organization of their molecules to micellar structures that act as soft templates for emerging polyaniline nanoparticles. The effect of AlCl3 is ascribed to the transformation of its molecules to [AlCl4]− anions.
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Sharma, Ravinder, Indra Bahadur, Manu Gautam, Mahmood M. S. Abdullah, Sangeeta Singh et Kaniki Tumba. « Interaction study of L-phenylalanine/glycyl-L-phenylalanine in water-soluble 1-decyl-3-methylimidazolium bromide ([C10mim]Br) ionic liquid : thermodynamic/physicochemical approaches ». Ionics, 19 janvier 2024. http://dx.doi.org/10.1007/s11581-023-05360-w.
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AbstractRecent times have witnessed notable progress in augmenting the effectiveness of pharmaceutical actions, leading to the creation of novel drug formulations and delivery technologies. A complete understanding of the molecular-level interactions between drug molecules and biological membranes is necessary to achieve optimal design in these processes. Comprehensive understanding of these interactions can be gained through thermodynamic research, which helps pharmaceutical professionals make well-informed decisions about which manufacturing compounds are most suited for a certain application. Because ionic liquids can interact with biological membranes and exert their effects on them, studying ionic liquids in combination with co-solvents in aqueous settings is important for many kinds of research. Using an Anton Paar DSA 5000 M apparatus, the densities, and speed of sound in a liquid mixture comprising L-phenylalanine and glycyl-L-phenylalanine within an aqueous 1-decyl-3-methylimidazolium bromide ([C10mim]Br), the ionic solution was measured. This was done across temperature ranges of 288.15 K, 298.15 K, 308.15 K, and 318.15 K and experimental pressure of p = 0.1 MPa with concentrations of “0.000, 0.005, 0.030, and 0.050 mol kg–1”. From the experimental results, various acoustic and physicochemical properties were derived, including apparent molar properties, partial compression, isentropic compression, and transfer properties. These computations provided insights into intermolecular interactions within the combination of 1-decyl-3-methylimidazolium bromide, water, L-phenylalanine, and glycyl-L-phenylalanine. The mixture’s characteristics were explored through pair and triplet coefficients, taking into account empirical constants and expansibilities, thereby delving into solute–solvent, hydrophilic-hydrophilic, dipole–dipole, and ion-hydrophilic interactions. Graphical Abstract
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Panda, Subhraraj. « Thermo-acoustic parameters of polymer dextran with aqueous sodium hydroxide : an ultrasonic study ». Current Materials Science 15 (17 août 2022). http://dx.doi.org/10.2174/2666145415666220817124330.
Texte intégralRésumé :
Aims: This study aimed to investigate the molecular interactions of dextran as a solute with sodium hydroxide as a solvent. Background: The propagation of ultrasonic waves through solids and liquids offers vital information on the structure of solids and liquids. The molecular interaction in pure liquids and liquid solutions has also been explored using ultrasonic speed estimates. The ultrasonic speed in a fluid provides a cutting-edge, feasible, and trustworthy technique for examining the characteristics of the polymer, amino acid, carbohydrate, and vitamin arrangements, among other things. It is mainly connected to the binding capacities of particles or molecules and has been successfully used in comprehending the concept of molecular interaction in liquid solution. Ultrasonic velocity measurement allows for the precise evaluation of several relevant acoustical characteristics that are particularly sensitive to molecular interactions. Objective: The acoustic and thermodynamic characteristics were utilised to investigate different types of interactions, molecular motion, and different interaction modes and their effects, which were impacted by the size of the pure component and the mixes. The significance provides subjective data on the nature and quality of particle interactions between solute and solvent in liquid solutions. Acoustic characteristics are important for evaluating the effect of temperature and frequency on the polymer dextran's aqueous sodium hydroxide solvent interactions. The density (ρ), viscosity, and ultrasonic speed (η) at 303 K, 308K, 313 K, 318K and 323K have been measured in the systems of polymer dextran with aqueous sodium hydroxide solution by using a pycnometer, Ostwald viscometer, and ultrasonic interferometer at frequencies at 1MHz, 5MHz, 9MHz, 12MHz, respectively. The acoustic parameters, such as free volume, internal pressure, attenuation coefficient, Rao’s constant, and Wada’s constant, are determined using the experimental parameters, including density (ρ), viscosity (η), and ultrasonic speed (U). Method: In this study, a pycnometer, an Ostwald's viscometer, and an ultrasonic interferometer to measure the density, viscosity, and ultrasonic velocity of the solution and compute the thermo-acoustic parameters based on the measured parameters were used. Result: Ultrasonic wave propagation affects the physical characteristics of the medium, providing information about liquid and solution. Conclusion: The effect of frequency and temperature on thermo-acoustic properties was studied. The aforementioned research has interpreted the nature of forces between molecules, such as hydrogen bonds, charge transfer complexes, and the breakdown of hydrogen bonds and complexes. Intermolecular forces are weak (electrostatic forces between charged particles having a permanent dipole and molecules with induced dipoles). The geometrical fitting of one molecule into another, owing to the variation in shape and size of the molecules, results in structural properties of the components. Other: In recent years, advances in ultrasonic methods have made them a potent instrument for assessing knowledge about the physical and chemical behaviour of liquid molecules. Due to its versatile pharmaceutical, biological, and contemporary uses, it has drawn analysts' attention to a new area of investigation. Consistent data on the physical and chemical characteristics of a wide range of liquid solutions are required.
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Zuniga, Ruth V., Jacob Kay, Jason Gruenhagen et Colin D. Medley. « Quantitation of conjugation-related residual solvents in antibody drug conjugates using headspace gas chromatography ». Current Pharmaceutical Analysis 16 (19 mai 2020). http://dx.doi.org/10.2174/1573412916999200519140817.
Texte intégralRésumé :
: Antibody Drug Conjugates (ADCs) are complex hybrid molecules comprised of a monoclonal antibody (mAb) connected to a small molecule drug through a linker. The key step in the production of ADCs is bringing together the protein in an aqueous buffer with a hydrophobic small molecule in order to achieve conjugation of the molecules. This step involves dissolving the small molecule portion of the compound in an aqueous miscible organic solvent. These solvents and unconjugated small molecules are ideally cleared by downstream processing in order to achieve the desired product quality. As part of the control system to ensure product quality, determination of residual solvents in pharmaceuticals is of significant importance in order to protect patient safety and ensure an efficacious drug. Headspace gas chromatography (HS-GC) is the most widely used tool for quantification of residual solvents for small molecule active pharmaceutical ingredients (APIs) but is not widely used for the analysis of protein containing samples. In this study, the detection of residual solvents in headspace injections was explored using various conditions in order to detect commonly used conjugation solvents including N,N-dimethylacetamide (DMA), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethylene glycol (EG), and propylene glycol (PG) in an ADC drug product sample. Various organic solvents were explored to enhance the response observed with complex protein and residual solvent matrixes. As EG and PG do not partition into the headspace efficiently in the ADC drug product samples that contain large amounts of water, ionic liquids and other ionic compounds were screened with the ADC samples to see if they could improve the partitioning of the key solvents EG and PG. Following headspace and chromatographic optimization, we have developed an approach for the detection and quantification of several conjugation reaction solvents in ADC samples. This new approach is a HS-GC method that simplifies gas chromatography (GC) analysis and sample preparation and can be readily implemented in quality control testing for bioconjugated products.
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Pramanik, Rajib, et Sagar Srivastava. « Modulation of Triton X-100 Aqueous Micelle Interface by Ionic Liquid : A Molecular Level Interaction Studied by Time-resolved Fluorescence Spectroscopy ». Current Physical Chemistry 14 (26 janvier 2024). http://dx.doi.org/10.2174/0118779468263953231022204147.
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Background: Self-assembly structure is an important area of research for understanding biological systems, owing to its resemblance to the membrane structure of the phospholipid bilayer. In a self-assembly medium, chemical reactions and chemical or physical processes are dramatically different than the bulk phase. Understanding this process in synthesizing self-assembly structures may allow us to explore various biological processes occurring in cell membranes. Objective: The study aimed to understand water dynamics in the TX-100 micellar interface via steady state and a time-resolved fluorescence spectroscopy study. The objective was also to determine the two different ionic liquids (ILs), namely 1-butyl-3-methyl imidazolium tetrafluoroborate ([bmim][BF4]) and 1-decyl-3-methyl imidazolium tetrafluoroborate ([dmim][BF4]), inducing surfactant aggregation changes at the molecular level. Also, the focus was on determining the hydration and its dynamics at the palisade layer of TX-100 micelle in the presence of two different ionic liquids. Methods: Steady state and time-resolved fluorescence spectroscopy have been used to study TX-100 micellar systems. Employing time-resolved spectroscopy, two chemical dynamic processes, solvation dynamics and rotational relaxation dynamics, have been studied to investigate structural changes in TX100 by adding ILs. Solvation dynamics was studied by measuring the time-dependent Stokes shift of the fluorescent probe. From the Stokes shift, time-resolved emission spectra were constructed to quantify the solvation dynamics. Also, using the polarization properties of light, time-resolved anisotropy was constructed to explore the rotation relaxation of the probe molecule. Results: The absorption and emission spectra of C-153 in TX-100 were red-shifted in the presence of both the ILs. Also, the C-153 experienced faster solvation dynamics and rotational relaxation with the addition of both ILs. In our previous study, we observed a significantly increased rate of solvation dynamics with the addition of [bmim][BF4] (J. Phys. Chem. B, 115, 6957-6963) [38]. However, with the addition of the same amount of [dmim][BF4], the IL rate of solvation enhancement was more pronounced than with [bmim][BF4]. The faster solvation and rotational relaxation have been found to be associated with the penetration of more free water at the TX100 micellar stern layer, leading to increased fluidity of the micellar interface. Conclusion: Upon incorporating ILs in TX100 micelle, substantially faster solvation dynamics of water as well as rotational relaxation dynamics of C-153 have been observed. By decreasing surfactant aggregations, [bmim][BF4] ILs facilitated more water molecules approaching the TX-100 micellar phase. On the other hand, [dmim][BF4] ILs comprising mixed micelles induced even more free water molecules at the palisade layer, yielding faster solvation dynamics in comparison to pure TX-100 micelle or TX100 micelle + [bmim][BF4] ILs systems. Time-resolved anisotropy study has also supported the finding and strengthened the solvation dynamics observation
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Syed Yaacob, Syed Fariq Fathullah, Nadia Mansor, Syaza Atikah Nizar, Ayo Olasupo, Norita Mohamed et Faiz Bukhari Mohd Suah. « Hybrid polymer inclusion membrane as anion exchange membrane for recovering Pd2+ ions in electrogenerative process ». Journal of Electrochemical Science and Engineering, 8 décembre 2022. http://dx.doi.org/10.5599/jese.1501.
Texte intégralRésumé :
A novel non-plasticized nano-porous hybrid inorganic-organic polymer inclusion membrane (PIM) was synthesized, characterized, and evaluated as an anion exchange membrane for application in electrogenerative processes to recover Pd2+ ions. Ionic liquids 1-ethyl-3-methylimidazolium chloride (EMIM-Cl) and 1-butyl-3-methylimidazolium chloride (BMIM-Cl) were used as the carrier molecules in the polymeric network of PIM to enhance anion exchange process. This hybrid anion exchange membrane also consists of a polymeric matrix of non-plasticized cellulose triacetate modified by incorporating an inorganic material (silane) prepared by the sol-gel route. Different parameters affecting the ion transport performance efficiency, i.e., the composition of the membrane, type of ionic liquid (carrier molecule) and ion–exchange capacity, were investigated and optimized. In the electrogenerative process, the results revealed that the prepared PIM yields better recovery results for recovering Pd2+ ions from its chloride solution compared to the commercial anion exchange membrane Neosepta® AM-01, with a full recovery of 100 mg/L Pd2+ ions in 30 min. This preliminary study shows that the prepared low-cost hybrid anion exchange membrane PIM can act as an inexpensive material suitable for the rapid and efficient recovery of Pd2+ ions from an aqueous solution.