- Solute-solvent interactions of amino acids in aqueous 1-propyl-3- methylimidazolium bromide ionic liquid solutions at 298.15 K
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Densities, viscosities, and refractive indices of three amino acids (glycine, L-alanine, and L-valine) in aqueous solutions of an ionic liquid, 1-propyl-3-methylimidazolium bromide, have been measured at 298.15 K. These data have been used to calculate apparent molar volumes (V φ ), viscosity B-coefficients, and molar refractions of these mixtures. The standard partial molar volumes (Vφ0) and standard partial molar volumes of transfer (Δtr Vφ0) have been determined for these amino acid solutions from these density data. The resulting values of Vφ0 and Δtr Vφ0 for transfer of amino acids from water to aqueous ionic liquid solutions have been interpreted in terms of solute + solvent interactions. These data also indicate that hydrophobic interactions predominate in L-alanine and L-valine solutions. Linear correlations were found for both Vφ0 and the viscosity B-coefficient with the number of carbon atoms in the alkyl chain of the amino acids, and have been used to estimate the contribution of the charged end groups ( NH+ 3, COO-), the CH2 group, and other alkyl chains of the amino acids. The viscosity and molar refractivity results have been used to confirm the conclusions obtained from volumetric properties.
- Shekaari, Hemayat,Jebali, Fatemeh
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- Electron density shift in imidazolium derivatives upon complexation with cucurbit[6]uril
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In this study, we have investigated the supramolecular interaction between series of l-alkyl-3-methylimidazolium guests with variable alkyl substituent lengths and cucurbit[6]uril (CB6) in the solution and the solid state. Correct interpretation of 1H NMR spectra was a key issue for determining the binding modes of the complexes in solution. Unusual chemical shifts of some protons in the 1H NMR spectra were explained by the polarization of the imidazolium aromatic ring upon the complexation with the host. The formation of 1:1 complex between 1 -ethyl-3-methylimidazolium and CB6 is in disagreement with previously reported findings describing an inclusion of two guest molecules in the CB6 cavity.
- Kolman, Viktor,Marek, Radek,Strelcova, Zora,Kulhanek, Petr,Necas, Marek,Svec, Jan,Sindelar, Vladimir
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- Extraction of cesium ions from aqueous solutions using calix[4]arene-bis(tert.octylbenzo-crown-6) in ionic liquids
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Solvent extraction of cesium ions from aqueous solution to hydrophobic ionic liquids without the introduction of an organophilic anion in the aqueous phase was demonstrated using calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) as an extractant. The selectivity of this extraction process toward cesium ions and the use of a sacrificial cation exchanger (NaBPh 4) to control loss of imidazolium cation to the aqueous solutions by ion exchange have been investigated.
- Luo, Huimin,Dai, Sheng,Bonnesen, Peter V.,Buchanan III,Holbrey, John D.,Bridges, Nicholas J.,Rogers, Robin D.
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- Comparative study between 1-Propyl-3-methylimidazolium bromide and trimethylene bis-methylimidazolium bromide ionic liquids by FTIR/ATR and FT-RAMAN spectroscopies
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In this study, we synthesized two ionic liquids based on imidazolium: one is a monocationic and the other is a dicationic. They are respectively 1-Propyl-3-methylimidazolium bromide ([PrMIM+][Br?]) and trimethylene bis-methylimidazolium bromide ([M(CH2)3IM2+][2Br?]). The structures of these two ionic liquids which are composed of ions with atoms of the same nature were first identified by 1H,13C NMR, and then compared in a study by FT-RAMAN and FTIR/ATR spectroscopies. FT-RAMAN spectras of the dicationic ionic liquid are richer in modes in the different spectral regions. Hence this richness seems to be a consequence of the passage from one to two rings in the imidazolium cation. In particular, the vibrational modes in the spectral ranges 700–600?cm?1, 1700–1500?cm?1 and 3200–2700?cm?1 by FTIR/ATR seem to be sensitive to the change from mono to dicationic than in FT-RAMAN. The spectral range in which the intermolecular interactions are present (200-50?cm?1) is a marker of differentiation between the mono and the dicationic. The spectral ranges on 1700–1200?cm?1 and 3200–2700?cm?1 also show signs of upheaval between our two samples. We can also notice that there are much more active modes in FT-RAMAN spectroscopy than in FTIR/ATR spectroscopy.
- Kadari, Mohamed,Belarbi, El Habib,Moumene, Taqiyeddine,Bresson, Serge,Haddad, Boumediene,Abbas, Ouissam,Khelifa, Brahim
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- Thermodynamic properties of 1-alkyl-3-methylimidazolium bromide ionic liquids
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Heat capacities and enthalpies of phase transitions for a series of 1-alkyl-3-methylimidazolium bromide ionic liquids have been measured by adiabatic calorimetry. Thermodynamic properties of the compounds were calculated in the temperature range of (5 to 370) K. Water was found to have an additive contribution to the heat capacities of [C4mim]Br in the liquid state above Tfus and in the solid state below 160 K at w(H2O) ≤ 5 · 10-3.
- Paulechka,Kabo,Blokhin,Shaplov,Lozinskaya,Vygodskii
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- Synthesis and surface functionalization of multi-walled carbon nanotubes with imidazolium and pyridinium-based ionic liquids: Thermal stability, dispersibility and hydrophobicity characteristics
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Functionalized multi-walled carbon nanotubes (MWCNTs) were synthesized by simple chemical method, and dispersed using imidazolium and pyridinium-based ionic liquids (ILs). The as-synthesized ILs-MWCNT composites were studied using FTIR spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), and solubility in different polar and non-polar solvents. Spectroscopic and microscopy analyses confirmed the formation of the ILs-MWCNT composites with new functionalities. Spectra studies showed graphitic and carboxylic groups in the pure MWCNTs. MWCNT SEM images showed entangled bundles, while ILs-MWCNTs showed debundled composites with increased diameter and unaltered MWCNTs morphology. TGA indicates that the MWCNTs are thermally stable which could be ascribed to van der Waals and non-covalent interactions within the composites matrices. Solubility studies indicate the ILs-MWCNT composites are hydrophobic, insoluble in water and other polar solvents.
- Matandabuzo, Mzukisi,Ajibade, Peter A.
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- Watching microwave-promoted chemistry: reaction monitoring using a digital camera interfaced with a scientific microwave apparatus
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By interfacing a digital camera with a scientific microwave unit it is possible to monitor macroscopic effects as reactions proceed, including color and viscosity changes, evolution of gases, metal-mediated couplings, and arcing.
- Bowman, Matthew D.,Leadbeater, Nicholas E.,Barnard, T. Michael
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- Binding studies on CB[6] with a series of 1-Alkyl-3-methylimidazolium ionic liquids in an aqueous system
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The host-guest chemistry between a series of 1-alkyl-3-methyl-imidazolium bromide ([Cnmim]Br) guests and the macrocyclic host molecule cucurbit[6]uril (CB[6]) in an aqueous system is systematically studied in neutral aqueous media. Both 1D and 2D NMR experiments in conjunction with isothermal titration calorimetry (ITC) unveil the binding characteristics of the host-guest interaction. Solution binding constants (Ka) up to 105m-1 are measured directly. Additionally, this [C nmim]Br-CB[6] interaction was found to significantly increase the solubility of CB[6] in neutral water, in some cases by at least four orders of magnitude. From these studies, a detailed host-guest binding model has been constructed and is fully discussed. In this model, the delocalized positive charge on the imidazolium ring becomes partially localized on either one of the nitrogen atoms upon complexation with CB[6]. Localization of the positive charge is directly related to the length of the "1-alkyl" chain on the imidazolium ring, which causes an induced local dipole subsequently allowing for an ion-dipole interaction with the carbonyl portal of CB[6].
- Zhao, Nan,Liu, Li,Biedermann, Frank,Scherman, Oren A.
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- Transition-metal-catalyzed reactions involving imidazolium salt/N-heterocyclic carbene couples as substrates
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Reactive Couples: Imidazolium salts react with alkenes under mild conditions in the presence of a Ni0-based catalyst to produce 2-alkyl imidazolium salts (see scheme, cod = 1,5-cyclooctadiene). The mechanism involves oxidative addition of an im
- Clement, Nicolas D.,Cavell, Kingsley J.
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- Properties of Bromine Fused Salts Based on Quaternary Ammonium Molecules and Their Relevance for Use in a Hydrogen Bromine Redox Flow Battery
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Bromine complexing agents (BCA) in aqueous electrolytes for hydrogen bromine flow batteries are used to reduce bromine‘s vapour pressure, while an insoluble and liquid fused salt is formed. The properties (concentrations, composition, conductivity and viscosity) of this fused salt are investigated in this study systematically ex situ by using 7 BCAs at different state of charge in HBr/Br2/H2O electrolytes with a theoretical capacity of 179.6 Ah L?1. Bromine is stored in the fused salt at concentrations up to 13.6 M, reaching theoretical volumetrical capacities up to 730 Ah L?1 in fused salts. The fused salt consists of a pure, bromine- and water-free ionic liquid of organic [BCA]+ cations and polybromides, and its conductivity bases on a hopping mechanism among the polybromides. Alkyl side chain length of the BCAs and distribution of polybromides influence strongly the conductivity and viscosity of the fused salts. 1-ethylpyridin-1-iumbromide results to be favoured BCA for application.
- Fischer, Peter,Küttinger, Michael,Loichet Torres, Paulette A.,Meyer, Emeline
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supporting information
(2022/02/21)
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- A Superstrong and Reversible Ionic Crystal-Based Adhesive Inspired by Ice Adhesion
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In this study, we developed a superstrong and reversible adhesive, which can possess a high bonding strength in the “adhesive” state and detach with the application of heating. An ionic crystal (IC) gel, in which an IC was immobilized within a soft-polymer matrix, were synthesized via in situ photo-crosslinking of a precursor solution composed of N, N-dimethyl acrylamide (DMAA) and a melted IC. The obtained IC gel is homogenous and transparent at melt point. When cooled to the phase transition temperature of the IC, the gel turns into the adhesive with the adhesion strength of 5.82 MPa (on glasses), due to the excellent wetting of melted gel and a thin layer of crystalline IC with high cohesive strength formed on the substrates. The synergistic effects between IC, polymer networks and substrates were investigated by solid state 1H NMR and molecular dynamics simulation. Such an adhesive layer is reversable and can be detached by heating and subsequent re-adhesion via cooling. This study proposed the new design of removable adhesives, which can be used in dynamic and complex environments.
- Liu, Lili,Liu, Ziyang,Ren, Yongyuan,Zou, Xiuyang,Peng, Wansu,Li, Weizheng,Wu, Yiqing,Zheng, Sijie,Wang, Xiaoliang,Yan, Feng
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supporting information
p. 8948 - 8959
(2021/03/16)
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- Preparation method of 1-R-3-methylimidazolyl ionic liquids with different chain lengths
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The invention discloses a preparation method of 1-R-3-methylimidazolyl ionic liquids with different chain lengths. The preparation method specifically comprises the following steps: step 1, under stirring, carrying out a thermostatic reaction on N-methylimidazole and 1-bromoalkane to obtain a first liquid; step 2, washing the first liquid with ethyl acetate until a supernatant is clear, and takinglower-layer liquid to obtain a second liquid; step 3, purifying the second liquid to obtain a crude product; and step 4, drying the crude product in vacuum to obtain the 1-R-3-methylimidazolyl ionicliquids with different chain lengths. The preparation method has the advantages that the preparation method is simple in process and easy to operate, used reagents are common, and cost is low; and the1-R-3-methylimidazolyl ionic liquids with different chain lengths and relatively high purity are prepared.
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Paragraph 0046-0051
(2020/05/11)
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- Controllable Homogeneity/Heterogeneity Switch of Imidazolium Ionic Liquids for CO2 Utilization
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Imidazolium ionic liquids (IL) have been recognized as a promising platform for CO2 capture and conversion owing to the structural designability through molecular combination of cationic substituents and counter anions. However, the conventiona
- Byun, Jeehye,Zhang, Kai A. I.
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p. 4610 - 4616
(2018/09/12)
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- Physicochemical properties of [Cnmim][TFA] (n = 2, 3, 4, 5, 6) ionic liquids
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A series of ionic liquids based on trifluoroacetic acid, namely, [Cnmim][TFA] (n = 2, 3, 4, 5, 6) (1-alkyl-3-methylimidazolium trifluoroacetate), were designed and synthesized. The density, surface tension and refractive index were measured in the temperature range of 293.15 to 343.15 ± 0.05 K, and some physicochemical properties of the ILs were calculated. Using the concept of molar surface Gibbs free energy, the traditional E?tv?s equation was improved into a modified E?tv?s equation, in which the intercept and the slope represented the molar surface enthalpy and the molar surface entropy, respectively, for [Cnmim][TFA] (n = 2, 3, 4, 5, 6). The thermal expansion coefficient (α) of [Cnmim][TFA] was calculated according to the interstitial model, and the order of magnitude of the calculated values was in good agreement with the corresponding experimental values. A new hypothesis was proposed, stating that the interstitial molar surface Gibbs free energy (gs) is not determined by the type of IL. From the refractive index and the molar surface Gibbs free energy, an equation to predict the surface tension of ILs was derived and the predicted values were highly correlated with the corresponding experimental values. Finally, a new polarity scale for ILs was developed, and the polarity order of the [Cnmim][TFA] (n = 2, 3, 4, 5, 6) ILs was estimated.
- Fang, Da-Wei,Zhang, Fang,Jia, Rui,Shan, Wei-jun,Xia, Li-xin,Yang, Jia-zhen
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p. 11616 - 11625
(2017/02/26)
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- A tungsten ion liquid and its preparation method and the catalytic olefin epoxidation of application (by machine translation)
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The invention relates to a tungsten ion liquid and its preparation method and the catalytic olefin epoxidation of application. A certain amount of tungsten ion liquid, oxidizing agent and of olefin substrate mixed, connect the condensate reflux device, accelerate the stirring rate, raising the temperature to 60 - 90 °C, reaction 1 - 8 h, stopping the reaction. The temperature drops to 30 - 50 °C, the extractant used extraction product, air admission chromatography, a yield of 97.6%. The invention uses a tungsten ion liquid is used as a catalyst, the process is simple, the reaction green is pollution-free, catalyst can be recycled, thereby protecting the environment, thereby greatly reducing the cost of the catalyst. (by machine translation)
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Paragraph 0023-0026
(2017/09/01)
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- Europium metal-organic frameworks as recyclable and selective turn-off fluorescent sensors for aniline detection
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Seven Eu-(H)BDC compounds, [RMI][Eu2(BDC)3Cl] (R = ethyl (1), propyl (2), butyl (3), H2BDC = 1,4-benzenedicarboxylic acid), [EMI]2[Eu2(BDC)3(H2BDC)Cl2] (4), [Eu(BDC)(HCOO)] (5), [Eu(BDC)Cl(H2O)] (6) and [Eu3(BDC)4Cl(H2O)6] (7), were synthesized under ionothermal conditions. Compounds 4 and 6 behave as potential highly selective turn-off fluorescent sensors for aniline, which can be detected in mixtures of aniline with contrast organic amides or alkylbenzenes. Fluorescence quenching can be observed when compounds 4 and 6 mix with the samples containing aniline. Compounds 4 and 6 show basically unchanged emission intensities and rapid response to aniline after ten recycling tests, suggesting that the compounds have high stable recycle repeatabilities.
- Feng, Hui-Jun,Xu, Ling,Liu, Bing,Jiao, Huan
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p. 17392 - 17400
(2016/11/13)
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- Estimation and structural effect on physicochemical properties of alkylimidazolium-based ionic liquids with different anions
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Ten kinds of alkylimidazolium-based aprotic ionic liquids (AILs) with hydrogen carbonate, dihydrogen phosphate, and hydrogen sulfate anions were prepared, and methods of elemental analysis, infrared spectroscopy, and proton nuclear magnetic resonance were employed to characterize the ILs, respectively. Properties such as electrical conductivity, density, dynamic viscosity, surface tension, were measured and correlated with thermodynamic and empirical equations over various temperature ranges under ambient conditions. Some significant thermodynamic parameters of the ILs were estimated. The trends of changing with temperature for the dynamic viscosity and the electrical conductivity were described by the Vogel-Fulcher-Tamman equation. The activation energies of dynamic viscosity and electrical conductivity were also calculated. Further, the structures and the energetics of the ILs ions were obtained through combining density functional theory calculations and the COSMO-RS methodology. The structural effects of ion variation on the properties of the ILs were studied.
- Zhang, Qingguo,Lan, Yalin,Liu, Hongwei,Zhang, Xinyuan,Zhang, Xuelei,Wei, Ying
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p. 2002 - 2012
(2016/07/06)
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- Combination effect of ionic liquid components on the structure and properties in 1,4-benzenedicarboxylate based zinc metal-organic frameworks
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Two types of 2D [RMI]2[Zn3(BDC)3X2] (Type A) and 3D [Zn(BDC)(H2O)] (Type B) (H2BDC = 1,4-benzenedicarboxylate acid) compounds were synthesized with three kinds of 1-alkyl-3-methyl imidazolium halide ([RMI]X) ionic liquids. Type A is the primary structure model showing a (3,6) network. Type B can be obtained from [BMI]Cl, [AMI]Cl and [AMI]Br media, showing a 4,4-connected {42·84} network. The structure, TG, and fluorescence analyses demonstrate the combination effect of the RMI+ templating effect and X- controlling the structure types. The boundary between Types A and B is from [PMI]Cl, via [BMI]Br, to [AMI]I as the reaction media. The decomposition temperatures of the compounds in Type A decrease with increased RMI+, while X- anions exert the influence that compounds containing Br- supply the highest thermal stability. Similarly, with increased RMI+, or X = I-, the compounds show red shifts compared to the emissions of the ligand.
- Zhang, Zong-Hui,Liu, Bing,Xu, Ling,Jiao, Huan
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p. 17980 - 17989
(2015/10/28)
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- Conductometric study of ionic liquids in the presence of N,N′-bis(2-pyridylmethylidene)-1,2-diiminoethane (BPIE) Schiff base in acetonitrile solutions at 298.15 K
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In recent years, Schiff bases and their metal complexes in the presence of ionic liquids (ILs) have been used in synthesis of various chemical compounds. To better understanding of ionic liquid influence on these processes, it is required to obtain information about the ion association behavior of the ionic liquids. Therefore, in this work, the molar conductivities of the ILs [RMIm]X (R= propyl, pentyl, and hexyl; X= Br- and Cl-) in different concentrations of N,N′-bis(2-pyridylmethylidene)-1,2-diiminoethane (BPIE) Schiff base + acetonitrile solutions were determined at 298.15 K. The obtained conductivity data were analyzed by low concentration Chemical Model (lcCM) conductivity equation to calculate the limiting molar conductivities (Λ0) and ion association constants (KA). The results show that BPIE, alkyl chain length of cation, and anion type have effect on the ionic association process of the ILs. The Λ0 and KA values decrease as the Schiff base concentration, alkyl chain length of cation, and anion size increase in the solution. The association constants were also used to calculate the standard Gibbs energy (ΔG0A) of ion-pairing association. The resulted ΔG0A values are negative and become more negative as the alkyl chain length of the cation and the size of anion increase. The large negative values of the standard Gibbs energy obtained for [HMIm]Br indicates the more spontaneity and the more feasibility of the association process for this ionic liquid.
- Shekaari, Hemayat,Kazempour, Amir,Khoshalhan, Maryam
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p. 360 - 365
(2015/02/19)
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- Molten ammonium salt as a solvent for menschutkin quaternization reaction (synthesis of ionic liquids) and other heterocyclic compounds
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An efficient one pot synthesis of ionic liquids (ILs) employing molten salt as a solvent is described. The imidazolium salts and pyridinium bromide and other heterocyclic compounds were synthesized using tetrabutylammonium halides as ionized solvents when melt. The yields were good and compounds were confirmed by their mass and spectral data. The utility of the method as a green one is suggested by comparing yield and kinetic time requirements with other known well established methods.
- Gupta, Gaurav R.,Chaudhari, Ganesh R.,Tomar, Preeti A.,Waghulade, Govinda P.,Patil, Keshar Singh J.
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experimental part
p. 4675 - 4678
(2012/08/27)
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- Synthesis and Glutathione Peroxidase-like activity of N-heterocyclic carbene derived cationic diselenides
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Water soluble cationic diselenide derivatives of benzimidazolin-2-selenones and imidazolin-2-selenones have been synthesized. The Glutathione Peroxidase-like (GPx-like) activities of cationic diselenides have been investigated for the first time. The GPx-like activities are found to be quite low as compared to the neutral imidazole based diselenide and intramolecularly coordinated diselenides. A mechanism for GPx-like activity has been proposed. The oxidation reactions of N-heterocyclic carbene derived selenones with hydrogen peroxide have been studied.
- Manjare, Sudesh T.,Singh, Harkesh B.,Butcher, Ray J.
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supporting information
p. 10561 - 10566,6
(2012/12/12)
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- Thermodynamic properties of salophen schiff base + ionic liquid ([C nmIm][Br]) + dimethylformamide ternary mixtures at 298.15 K
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The densities and viscosities of ternary mixtures of N,N′- salicylidenephenylenediamine Schiff base (Salophen) + ionic liquid + N,N-dimethylformamide (DMF) have been determined at 298.15 K and at atmospheric pressure. The ionic liquids were: 1-propyl-3-me
- Shekaari, Hemayat,Bezaatpour, Abolfazl,Elhami-Kalvanagh, Rasoul
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experimental part
p. 345 - 351
(2012/05/20)
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- Ionic liquids promote PCR amplification of DNA
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A bicyclic imidazolium ionic liquid (4d), [b-4C-im][Br], was found to be highly effective not only for promoting PCR of GC-rich DNA by minimizing non-specific amplification, but also for facilitating PCR of normal-GC DNA under mild conditions.
- Shi, Yugang,Liu, Yen-Liang,Lai, Peng-Yeh,Tseng, Ming-Chung,Tseng, Min-Jen,Li, Yudong,Chu, Yen-Ho
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supporting information; experimental part
p. 5325 - 5327
(2012/06/30)
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- Microwave-assisted synthesis and spectral identification of [Rmim]PF 6 (R = p,b,c6) ionic liquids
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By microwave irradiation, the intermediates of imidazolium ionic liquids: 1-Butyl-3-methylimidazolium bromide ([bmim]Br), 1-propyl-3-methylimidazolium bromide ([pmim]Br), 1-hexyl-3-methylimidazolium bromide ([c6mim]Br) were synthesized, respectively from 1-methylimidazole and organic bromide(1-bromobutane, 1-bromopropane, 1-bromohexane). The optimal technological conditions were obtained by the crossed experiment, i.e., 1-methylimidazole/ organic halide (in mole): 1:1.1, temperature: 80 °C, time: 20 min. The product yield was 90 % and more. Each of them reacted with HPF6 for 4 h at room temperature, respectively to get hydrophobic imidazolium ionic liquids, i.e., 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim]PF 6), 1-propyl-3-methyl-imidazolium hexafluorophosphate ([pmim]PF 6), 1-hexane-3-methyl-imidazolium hexafluorophosphate ([c 6mim]PF6). The product yield was about 50 %. Their structures were analyzed and identified by UV-vis, IR and H' NMR spectra, respectively.
- Yongqing, Su,Yongfu, He,Cong, Li,Ping, Wang,Yun, Zhong,Limei, Liu,Fei, He
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experimental part
p. 97 - 99
(2011/11/28)
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- Effect of N, N'-bis(2-pyridylmethylidene)-1,2-diiminoethane (BPIE) schiff base on the thermophysical properties of ionic liquids in N, N -dimethylformamide solutions at 298.15 K
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Various thermophysical properties, densities, electrical conductances, viscosities, and refractive indices of two ionic liquids, 1-pentyl-3- methylimidazolium bromide ([PnMIm]Br) and 1-propyl-3-methylimidazolium bromide ([PMIm]Br, in the presence of N,N'-bis(2-pyridylmethylidene)-1,2-diiminoethane (BPIE) Schiff base in N,N-dimethylformamide (DMF) solutions have been measured at 298.15 K. These data have been used to calculate the standard partial molar volumes, Vφ0, partial molar volumes of transfer, ΔtrVφ0, ion association constants, Ka, limiting molar conductivities, λ0, viscosity B-coefficients, and molar refractions, RD, for the solutions studied. These parameters decrease with increasing BPIE concentration and increase with increasing alkyl chain length of ionic liquids. The results were interpreted in terms of cosphere overlap model and solute-solvent interactions. In general, it is concluded that there is an enhancement in the nonpolar-nonpolar interactions between the BPIE Schiff base and the ionic liquid.
- Shekaari, Hemayat,Bezaatpour, Abolfazl,Khoshalhan, Maryam
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body text
p. 4164 - 4172
(2012/03/10)
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- TRIAZOLIUM AND IMIDAZOLIUM SALTS AND USES THEREOF
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The present disclosure relates to certain new and known triazolium and/or imidazolium salts and to their therapeutic use, for example in methods of treating or preventing an infection by a Plasmodium or Babesia parasite in a subject in need thereof. The triazolium and imidazolium salts are compounds of the Formula (I) or (II): wherein R1-R4, R1′-R3′, R8-R11, X, X′, X″, Y, Y′ and Y″ are as defined in the disclosure.
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Page/Page column 26
(2011/10/31)
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- Anti-Plasmodium activity of imidazolium and triazolium salts
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We have previously reported that tetrazolium salts were both potent and specific inhibitors of Plasmodium replication, and that they appear to interact with a parasite component that is both essential and conserved. The use of tetrazolium salts in vivo is limited by the potential reduction of the tetrazolium ring to form an inactive, neutral acyclic formazan. To address this issue imidazolium and triazolium salts were synthesized and evaluated as Plasmodium inhibitors. Many of the imidazolium and triazolium salts were highly potent with active concentrations in the nanomolar range in Plasmodium falciparum cultures, and specific to Plasmodium with highly favorable therapeutic ratios. The results corroborate our hypothesis that an electron-deficient core is required so that the compound may thereby interact with a negatively charged moiety on the parasite merozoite; the side groups in the compound then form favorable interactions with adjacent parasite components and thereby determine both the potency and selectivity of the compound.
- Vlahakis, Jason Z.,Lazar, Carmen,Crandall, Ian E.,Szarek, Walter A.
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experimental part
p. 6184 - 6196
(2010/09/14)
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- Synthesis, structure, and physico-optical properties of manganate(II)-based ionic liquids
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Several ionic liquids (ILs) based on complex manganate(II) anions with chloro, bromo, and bis(trifluoromethanesulfonyl)amido (Tf2N) ligands have been synthesized. As counterions, n-alkyl-methylimidazolium (C nmin) cations of different chain length (alkyl = ethyl (C 2), propyl (C3), butyl (C4), hexyl (C 6)) were chosen. Except for the 1-hexyl-3-methylimidazolium ILs, all of the prepared compounds could be obtained in a crystalline state at room temperature. However, each of the compounds displayed a strong tendency to form a supercooled liquid. Generally, solidification via a glass transition took place below -40°C. Consequently, all of these compounds can be regarded as ionic liquids. Depending on the local coordination environment of Mn 2+, green (tetrahedrally coordinated Mn2+) or red (octahedrally coordinated Mn2+) luminescence emission from the 4T(G) level is observed.[1] The local coordination of the luminescent Mn2+ centre has been unequivocally established by UV/Vis as well as Raman and IR vibrational spectroscopies. Emission decay times measured at room temperature in the solid state (crystalline or powder) were generally a few ms, although, depending on the ligand, values of up to 25 ms were obtained. For the bromo compounds, the luminescence decay times proved to be almost independent of the physical state and the temperature. However, for the chloro- and bis(trifluoromethanesulfonyl)amido ILs, the emission decay times were found to be dependent on the temperature even in the solid state, indicating that the measured values are strongly influenced by nuclear motion and the vibration of the atoms. In the liquid state, the luminescence of tetrahedrally coordinated Mn2+ could only be observed when the tetrachloromanganate ILs were diluted with the respective halide ILs. However, for [C3mim][Mn(Tf2N)3], in which Mn 2+ is in an octahedral coordination environment, a weak red emission from the pure compound was found even in the liquid state at elevated temperatures.
- Pitula, Slawomir,Mudring, Anja-Verena
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experimental part
p. 3355 - 3365
(2010/06/21)
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- Imidazolium bromide-based ionic liquid assisted improved activity of trypsin in cationic reverse micelles
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The present work reports the imidazolium-based ionic liquids (ILs) assisted enhancement in activity of water-pool solubilized enzyme trypsin in cationic reverse micelles of CTAB. A set of imidazolium ILs (1-alkyl-3-methyl imidazolium bromides) were prepared with varying lengths of their side armwhich results in the differential location of these organic salts in the reverse micelles. The different ILs offered varied activating effects on the biocatalyst. The activity of trypsin improved 30-300% in the presence of 0.1-10 mM of different ILs in reverse micelles of CTAB. Trypsin showed 300% (4-fold) increment in its activity in the presence of IL2 (1-ethyl-3-methyl imidazoliumbromide,EMIMBr) compared to that observed in the absence of IL in CTAB reverse micelles. The imidazolium moiety of the IL, resembling the histidine amino acid component of the catalytic triad of hydrolases and itsBr- counterion, presumably increases the nucleophilicity of water in the vicinity of the enzyme by forming a hydrogen bond that facilitates the enzyme-catalyzed hydrolysis of the ester.However, the ILs with increasing amphiphilic character had little to no effect on the activity of trypsin due to their increased distance from the biocatalyst, as they tend to get localized toward the interfacial region of the aggregates. Dynamic light scattering experimentationwas carried out in the presence of ILs to find a possible correlation between the trypsin activity and the size of the aggregates. In concurrencewith the observed highest activity in the presence of IL2, the circular dichroism (CD) spectrum of trypsin in CTAB reverse micelles doped with IL 2 exhibited the lowest mean residue ellipticity (MRE), which is closest to that of the native protein in aqueous buffer.
- Debnath, Sisir,Das, Dibyendu,Dutta, Sounak,Das, Prasanta Kumar
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experimental part
p. 4080 - 4086
(2011/11/06)
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- Multiple cobalt phosphate ring system from l-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids
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Open-framework phosphate Co7(PO4) 2(HPO4)4 with a multiple ring system was ionothermally synthesized by using 1-alkyl -3-methylimidazolium tetrafiuoroborates as solvent. The crystals of Co7(PO 4)2(HPO4)4 were large enough to do single crystal X-ray diffraction analysis, which crystallize in the space group P-1 (No.2), with cell parameters of α = 6.471(3) A, b = 7.881(3) A, c = 9.488(4) A, α = 104.288(6)°, β = 109.062(5)° and γ = 101.345(5)°. The systematic increase in alkyl chain length from 2 to 4 carbon atoms in l-alkyl-3-methylimidazolium tetrafluoroborates was investigated in this ionothermal synthesis system. The effect of different anions, such as Cl - , Br - and BF4 - , on the synthesis result will also be presented in this paper.
- Yang, Miao,Liu, Qingshan,Yan, Peifang,Liu, Xiumei,Welz-Biermann, Urs
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experimental part
p. 97 - 104
(2010/06/19)
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- Nanohybrid materials from the intercalation of imidazolium ionic liquids in kaolinite
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A series of novel organic-inorganic nanohybrid materials were obtained by the intercalation in the interlamellar spaces of the clay mineral kaolinite, of ionic liquids based on imidazolium derivatives. The intercalation procedure was successfully accomplished via a melt reaction strategy using the dimethylsulfoxide-kaolinite intercalate (DMSO-K) as a precursor. 13C MAS NMR as well as XRD, TGA/DTA and FTIR studies confirmed the complete displacement of DMSO molecules by the imidazolium salts during the intercalation process. Increase of the basal spacing from 1.1 nm in DMSO-K to 1.3-1.7 nm in the nanohybrid materials was observed, indicating that imidazolium derivatives are oriented in a way such that the imidazole ring is parallel, or slightly tilted by an angle of 10-25°, with respect to the kaolinite internal surfaces. The number of moles of organic material loaded in the nanohybrids was obtained from several independent measurements. The intercalation of the imidazolium salts increases the thermal stability of the resulting material by more than 150 °C with respect to DMSO-K. After heating under air at 300 °C for two hours, XRD showed that the structure of the intercalates was kept with only a slight decrease of the intercalation ratio. The original kaolinite structure was recovered after heating the intercalate at 350 °C for an additional two hours. This observed high thermal stability is promising for the use of these nanohybrid materials as precursor for the synthesis of new nanocomposites by incorporation of polymer in kaolinite at high temperature. The Royal Society of Chemistry.
- Letaief, Sadok,Detellier, Christian
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p. 1476 - 1484
(2008/02/04)
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- Synthesis and properties of N,N′-dialkylimidazolium bis(nonafluorobutane-1-sulfonyl)imides: A new subfamily of ionic liquids
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A series of N,N′-dialkylimidazolium bis(nonafluorobutane-1-sulfonyl) imides was synthesized in high yields by quaternization of imidazole derivatives with various readily available alkylating reagents, followed by anion exchange with highly stable and non-hygroscopic potassium bis(nonafluorobutane-1- sulfonyl)imide. The latter was obtained by an improved method starting from ammonium chloride and nonafluorobutane-1-sulfonyl fluoride. The quaternary imidazolium salts thus obtained constitute a new subfamily of thermally stable and remarkably hydrophobic ionic liquids with melting points in the range 0-40°C and solubilities in water and organic solvents (aromatic hydrocarbons, dialkyl ethers) in the range of 0.5-1.5 wt%. The ionic liquids can be easily purified from ionic byproducts (e.g., halogenide salts) by aqueous extraction followed by thorough drying in a high vacuum without loss of yield. Due to the above features, these new ionic fluids may be considered as promising recyclable media in repeated catalytic processes.
- Quek, Ser Kiang,Lyapkalo, Ilya M.,Huynh, Han Vinh
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p. 3137 - 3145
(2007/10/03)
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- Physical and electrochemical properties of 1-alkyl-3-methylimidazolium tetrafluoroborate for electrolyte
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Three kinds of ionic liquids, 1-alkyl-3-methylimidazolium tetrafluoroborate (n = 2-4), were prepared and fundamental properties of ionic liquids and those mixed with industrially used organic solvents (PC, GBL and AN) were investigated compared to solid salts, TEMABF4. It was found that degree of ionization of the ionic liquids were almost same as that of TEMABF4 from the conductivity measurement in diluted system of PC. The ionic liquids and the organic solvents intermingle with each other. Some enhancement in conductivity was observed compared to TEMABF4.
- Nishida, Tetsou,Tashiro, Yasutaka,Yamamoto, Masashi
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p. 135 - 141
(2007/10/03)
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- Method for prepararing alkoxyamines from nitroxides
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The invention concerns a method for preparing alkoxyamines in a biphasic medium. Said method consists in mixing an ionic liquid, an organic solvent, a metal salt, a metal ligand, a halogeno-carbonaceous ZX compound and a nitroxide, maintaining the reaction medium under agitation at a temperature between 20° C. and 90° C., until the nitroxide is eliminated, decanting, recuperating the organic phase, optionally washing it with water and then in isolating the alkoxyamine by evaporating the organic solvent under reduced pressure.
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- Solvent-free sonochemical preparation of ionic liquids.
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[reaction: see text] An ultrasound-assisted preparation of a series of ambient-temperature ionic liquids, 1-alkyl-3-methylimidazolium (AMIM) halides, which proceeds via efficient reaction of 1-methyl imidazole with alkyl halides/terminal dihalides under solvent-free conditions, is described.
- Namboodiri, Vasudevan V,Varma, Rajender S
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p. 3161 - 3163
(2007/10/03)
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- Microwave-assisted synthesis of room-temperature ionic liquid precursor in closed vessel
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We report here the synthesis of various alkylpyridinium and 1-alkyl-3-methylimidazolium halides on a large scale under microwave irradiation, in a closed vessel. The reaction time was drastically reduced as compared to conventional methods, and good yields were obtained.
- Khadilkar, Bhushan M.,Rebeiro, Geeta L.
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p. 826 - 828
(2013/09/06)
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- Coordination Chemistry and Mechanisms of Metal-Catalyzed C-C Coupling Reactions, Part 12. Nonaqueous Ionic Liquids: Superior Reaction Media for the Catalytic Heck-Vinylation of Chloroarenes
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Nonaqueous ionic liquids, that is molten salts, constitute an activating and stabilizing noninnocent solvent for the palladium-catalyzed Heck-vinylation of all types of aryl halides. Especially with chloroarenes an improved activity and stability of almost any known catalyst system is observed as compared to convetional, molecular solvents (e.g. dimethylformamide (DMF), dimethylacetamide (DMAc), N-methyl-2-pyrrolidinone (NMP), or dioxane). Thus, even catalytic amounts of ligand-free PdCl2 yield stilbene from technically interesting chlorobenzene and styrene in high yield (turnover number (TON) = 18) without the need for further promoting salt additives such as tetraphenylphosphonium chloride. The scope of the new reaction medium is outlined for the first time for the vinylation of various aryl halides using different mono- and disubstituted olefins as well as a variety of known palladium(0) and palladium(II) catalyst systems. Furthermore, a novel means of catalyst recycling is presented and its scope is evaluated.
- Boehm, Volker P. W.,Herrmann, Wolfgang A.
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p. 1017 - 1025
(2007/10/03)
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- THE EFFECT OF POLYMERIC AND MODEL IMIDAZOLIUM HALIDES ON THE RATE OF HYDROLYSIS OF 4-ACETOXY-3-NITROBENZOIC ACID
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The course of hydrolysis of an ester, 4-acetoxy-3-nitrobenzoic acid catalyzed with poly(1-methyl-3-allylimidazolium bromide) (IIa), poly (IIb) and poly (IIc) in a 28.5percent aqueous ethanol was investigated as a function of pH and compared with low-molecular weight models, viz., 1-methyl-3-alkylimidazolium bromides (the alkyl group being methyl, propyl, and hexyl, resp).Polymers IIb, IIc possessed a higher activity at pH above 9, while the models were more active at a lower pH with a maximum at pH 7.67.The catalytic activity at the higher pH is attributed to an attack by the OH- group, while at the lower pH it is assigned to a direct attack of water on the substrate.The rate of hydrolysis of 4-acetoxy-3-nitrobenzoic acid is proportional to the catalyst concentration and proceeds as a first-order reaction.The hydrolysis depends on the composition of the solvent and was highest at 28.5percent (vol.) of ethanol in water.The hydrolysis of a neutral ester, 4-nitrophenyl acetate, was not accelerated by IIc.
- Sorm, Miloslav,Prochazka, Miloslav,Kalal, Jaroslav
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p. 845 - 853
(2007/10/02)
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- ORGANIC SEMICONDUCTORS: SIMPLE AND COMPLEX SALTS OF 1-METHYL-3-ALKYLIMIDAZOLIUM 7,7,8,8-TETRACYANO-p-QUINODIMETHANE
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By metathesis between lithium salts of 7,7,8,8-tetracyano-p-quinodimethane and 1-methyl-3-alkylimidazolium bromides, simple radical salts were prepared whose specific electrical conductivity values are c. 10-7 - 10-3, Ω-1 m-1, according to the donor structure.Combining these salts with neutral 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) gave complex salts with an electrical conductivity higher by 7-3 orders of magnitude which increases monotonically with increasing volume of the alkyl group.The compounds are stable in anhydrous conditions also in presence of oxygen, and if irradiated by daylight.The rate constant of hydrolysis of these salts is proportional to the water content in solution and inversely proportional to the content of neutral TCNQ in the simple radical salt.The hydrolysis is predominantly activated by light absorbed by the decomposition products.
- Sorm, Miloslav,Nespurek, Stanislav,Prochazka, Miloslav,Koropecky, Igor
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p. 103 - 111
(2007/10/02)
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