- Ionothermal synthesis, structures, properties of cobalt-1,4-benzenedicarboxylate metal-organic frameworks
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Eight kinds of 1-methyl-3-alkylimidazolium halide [RMI]X (R=ethyl (E), propyl (P), butyl (B) and amyl (A); MI = imidazolium; X= Cl-, I-) ionic liquids (ILs) were used as reaction media and obtained a series of 2D [RMI]2[Co3(BDC)3X2] frameworks through the ionothermal reactions of 1,4-benzenedicarboxylic acid (H2BDC) with Co(NO3)2·6H2O. The 2D [RMI]2[Co3(BDC)3X2] frameworks exhibit a same (3,6) topology network with [RMI]+ cations locating in the interlayer space. [RMI]+ cations play a template role in the structure constructions, whose influence combining with the effect of X- anions pass to the TG behaviors. The decomposition temperatures of the [RMI]2[Co3(BDC)3X2] frameworks decrease with the alkyl chains in [RMI]+ cations, and the compounds containing Cl- show higher thermal stabilities than those with I-. However, compounds 1-8 exhibit two similar broad emissions at ca. 380 and 390 nm, assigned to ILCT. The RMI+ templates and the X- anions do not exert their influence on the fluorescence.
- Zhang, Zong-Hui,Xu, Ling,Jiao, Huan
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- Influence of imidazolium bis(trifluoromethylsulfonylimide)s on the rotation of spin probes comprising ionic and hydrogen bonding groups
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The influence of the alkyl chain length in 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonylimide)s is studied to explore the rotation of piperidine-1-yloxyl derivatives substituted with either hydrogen bonding hydroxy group or ionic substituents, such as the cationic trimethylammonium or the anionic sulfate group placed at the 4 position. Structural variation of the ionic liquids results in differences of their viscosity influencing the rotation of the spin probes. The size of the average rotational correlation times of the spin probes dissolved in the ionic liquids depends further on the additional substituent in 4-position at these spin probes. The rotational correlation time exhibits a linear dependence on the ionic liquid viscosity in the case of the spin probe forming hydrogen bonding with the ionic liquids. In contrast to this, a deviation from the Stokes-Einstein behavior is found in the case of rotation of the charged spin probes in the 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonylimide)s substituted with a longer alkyl chain. This effect may be explained by phase separation on a molecular level between the charged part of the ionic liquid and the longer alkyl chains bound at the imidazolium ion. Although the neutral and the cationic spin probes show only a slight dependence between ionic liquid structure variation and the hyperfine coupling constants, structural effects cause changes in the hyperfine coupling constants in the case of the anionic spin probes. These probes strongly interact with the imidazolium ion.
- Strehmel, Veronika,Rexhausen, Hans,Strauch, Peter
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- Towards Safer Rocket Fuels: Hypergolic Imidazolylidene-Borane Compounds as Replacements for Hydrazine Derivatives
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Currently, toxic and volatile hydrazine derivatives are still the main fuel choices for liquid bipropellants, especially in some traditional rocket propulsion systems. Therefore, the search for safer hypergolic fuels as replacements for hydrazine derivatives has been one of the most challenging tasks. In this study, six imidazolylidene-borane compounds with zwitterionic structure have been synthesized and characterized, and their hypergolic reactivity has been studied. As expected, these compounds exhibited fast spontaneous combustion upon contact with white fuming nitric acid (WFNA). Among them, compound 5 showed excellent integrated properties including wide liquid operating range (?70–160 °C), superior loading density (0.99 g cm?3), ultrafast ignition delay times with WFNA (15 ms), and high specific impulse (303.5 s), suggesting promising application potential as safer hypergolic fuels in liquid bipropellant formulations.
- Huang, Shi,Qi, Xiujuan,Liu, Tianlin,Wang, Kangcai,Zhang, Wenquan,Li, Jianlin,Zhang, Qinghua
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- A study of the ionic liquid mediated microwave heating of organic solvents
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The use of ionic liquids as aids for microwave heating of nonpolar solvents has been investigated. We show that hexane and toluene together with solvents such as THF and dioxane can be heated way above their boiling point in sealed vessels using a small q
- Leadbeater, Nicholas E.,Torenius, Hanna M.
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- A Cation-Tethered Flowable Polymeric Interface for Enabling Stable Deposition of Metallic Lithium
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A fundamental challenge, shared across many energy storage devices, is the complexity of electrochemistry at the electrode-electrolyte interfaces that impacts the Coulombic efficiency, operational rate capability, and lifetime. Specifically, in energy-dense lithium metal batteries, the charging/discharging process results in structural heterogeneities of the metal anode, leading to battery failure by short-circuit and capacity fade. In this work, we take advantage of organic cations with lower reduction potential than lithium to build an electrically responsive polymer interface that not only adapts to morphological perturbations during electrodeposition and stripping but also modulates the lithium ion migration pathways to eliminate surface roughening. We find that this concept can enable prolonging the long-term cycling of a high-voltage lithium metal battery by at least twofold compared to bare lithium metal.
- Huang, Zhuojun,Choudhury, Snehashis,Gong, Huaxin,Cui, Yi,Bao, Zhenan
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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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- PEGylated imidazolium ionic liquid electrolytes: Thermophysical and electrochemical properties
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We report the synthesis and characterization of a series of imidazolium iodide ionic liquids (ILs) containing monomethoxy-terminated poly(ethylene glycol) (mPEG), and n-alkyl groups. These PEGylated ILs contain 7, 12, or 16 ethylene glycol units in the si
- Ganapatibhotla, Lalitha V.N.R.,Zheng, Jianping,Roy, Dipankar,Krishnan, Sitaraman
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- Influence of methyl and propyl groups on the vibrational spectra of two imidazolium ionic liquids and their non-ionic precursors
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Imidazolium-based ionic liquids (ILs) are usually synthesized using non-ionic imidazole compounds as precursors. While the ILs have been extensively studied in the past, the precursors was not paid much attention to. The structural analysis of the precursors, however, may offer an opportunity to better understand the behavior of the ionic compounds of interest. In this paper, a comparative study of two ionic liquids and their imidazole precursors is presented. The precursors 1-methylimidazole [1-MIM] and 1,2-dimethylimidazole [1,2-DMIM] are compared in order to explain the influences of the methyl group at the C(2) position (methylation). Since the imidazole compounds are non-ionic, the spectroscopic properties of [1-MIM] and [1,2-DMIM] are not affected by cation-anion interactions. In addition, the products obtained by alkylation using propyl iodide leading to the corresponding IL compounds 1-methyl-3-propylimidazolium iodide [1-MPrIM+][I?] and 1,2-dimethyl-3-propylimidazolium iodide [1,2-DMPrIM+][I?] were studied. For this purpose, vibrational spectroscopy in terms of FT-Raman and FTIR in the wavenumber range from [45 to 3500?cm?1] and from [600 to 4000?cm?1], respectively, was performed. Moreover, to aid the spectral assignment, density functional theory (DFT) calculations were carried out. The aim was to investigate the vibrational structure, to understand the effects of the propyl group at the N(3) and of the methyl group at the C(2) position, and to analyze the resulting cation-anion interactions. The data indicate that the iodide ion predominantly interacts with the C(2)[sbnd]H group via hydrogen bonding. Upon methylation, the C(4/5)[sbnd]H moiety becomes the main interaction site. However, an interaction takes place only with one of the two hydrogen atoms resulting in a split of the initially degenerate CH stretching modes.
- Haddad, Boumediene,Mokhtar, Drai,Goussem, Mimanne,Belarbi, El-habib,Villemin, Didier,Bresson, Serge,Rahmouni, Mustapha,Dhumal, Nilesh R.,Kim, Hyung J.,Kiefer, Johannes
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- Poly(ionic liquid)/ionic liquid/graphene oxide composite quasi solid-state electrolytes for dye sensitized solar cells
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Poly(ionic liquid)/ionic liquid/graphene oxide (poly(IL)/IL/GO) composite gel electrolytes containing poly(1-butyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide), 1-propyl-3-methylimidazolium iodide and graphene oxide are prepared for dye-sensitized solar cells (DSSCs), without any volatile organic solvent. The conductivity of the composite electrolyte is significantly increased by adding an appropriate amount of GO, and the DSSCs based on composite electrolytes containing GO show higher power conversion efficiency performance and better long-term stability compared to those without GO. The DSSC based on the composite electrolytes which contain 2 wt% of GO show an overall power conversion efficiency of 4.83% under simulated AM 1.5 solar spectrum irradiation. The superior long-term stability of the DSSCs indicates that this type of composite electrolyte could overcome the drawbacks of volatile liquid electrolytes, and offer a feasible method to fabricate DSSCs in future practical applications.
- Lin, Bencai,Feng, Tianying,Chu, Fuqiang,Zhang, Shuai,Yuan, Ningyi,Qiao, Gang,Ding, Jianning
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- Stable wire-shaped dye-sensitized solar cells based on eutectic melts
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Wire-shaped dye-sensitized solar cells (DSCs) have recently attracted increasing interest due to their unique and promising advantages, such as being lightweight, deformable and weavable compared to conventional planar structures. However, the use of liquid electrolytes based on organic solvents has largely limited their practical applications, e.g., low mechanical and thermal stabilities. Solid-state electrolytes are resistive to these problems in nature, and have been shown to have high stability. Herein, eutectic melts, for the first time, have been introduced as the electrolyte to develop novel wire-shaped DSCs. The resulting wire-shaped DSCs were flexible and highly stable thermally and their energy conversion efficiencies could recover entirely after heating up to 110 °C.
- Li, Houpu,Yang, Zhibin,Qiu, Longbin,Fang, Xin,Sun, Hao,Chen, Peining,Pan, Shaowu,Peng, Huisheng
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- Extraordinary aspects of bromo-functionalized multi-walled carbon nanotubes as initiator for polymerization of ionic liquid monomers
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Two ionic liquid monomers, 1-(2-acryloyloxy-ethyl)-3-methyl-imidazol-1-ium iodide (AMImI) and 1-(2-acryloyloxy-ethyl)-3-methyl-benzoimidazol-1-ium iodide (AMBImI), were synthesized and polymerized through atom transfer radical polymerization (ATRP). Poly(AMImI)-grafted multi-walled carbon nanotubes (denoted as MWCNT-poly(AMImI)) could also be fabricated through "grafting from" method of ATRP using bromo-functionalized MWCNT (denoted as MWCNT-Br) as initiator but MWCNT-poly(AMBImI) could not. Based on the thermogravimetric analysis and high resolution transmission electron microscopy, AMBImI monomer has encapsulated the MWCNT-Br probably through the π-π and cation-π interactions invalidating the initiation capability of MWCNT-Br. Besides, by mixing AMBImI with MWCNT-Br directly at room temperature, the MWCNT-Br was coated with a thin layer of AMBImI, whereas MWCNT-Br could not physisorb AMImI. Both MWCNT-poly(AMImI) and AMBImI-encapsulated MWCNT were dispersed well in 1-methyl-3-propylimidazolium iodide ionic liquid.
- Chang, Yu-Hsun,Lin, Pei-Yi,Wu, Ming-Sung,Lin, King-Fu
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- Influence of Cation Size and Polarity on Charge Transport in Ionic Liquid Based Electrolytes
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Imidazolium-based ionic liquids (ILs) with allyl and ether side chains were synthesized and characterized. Comprehensive structural and photoelectrochemical characterizations were performed, transport properties of ILs were also examined as electrolyte components in dye sensitized solar cells (DSSCs). The properties of synthesized materials and DSSC performances were compared with 1-propyl-3-methyl imidazolium iodide (PMII) and 1-allyl-3-ethyl imidazolium iodide (AEII) as reference ILs. Ionic conductivities, diffusion coefficients and charge transfer resistances of synthesized ionic liquids were investigated on DSSCs by Electrochemical Impedance Spectroscopy (EIS). The diffusion coefficient values of triiodide ions in different ionic liquid-based electrolytes were measured by the means of diffusion limited current density method and found to be 1.75×10?7 cm2 s?1 and 2.05×10?7 cm2 s?1 with corresponding photocurrent densities of 10.38 mAcm?2 and 12.13 mAcm?2 for the reference AEII and PMII based electrolytes, respectively. However, for the electrolytes of 1-(2-methoxyethyl)-3-allyl imidazolium iodide and 1-allyl-3-methyl imidazolium iodide ionic liquids, these values were found to be 0.86×10?7 cm2 s?1 and 0.57×10?7 cm2 s?1 with photocurrent densities of 9.53 mAcm?2 and 8.98 mAcm?2, respectively. Allyl and ether substituted imidazolium ILs exhibited promising results as potential alternative electrolyte materials for DSSCs.
- Aydin, Banu,Oner, Saliha,Varlikli, Canan,Zafer, Ceylan
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- Photocatalytic C-F Bond Borylation of Polyfluoroarenes with NHC-boranes
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The first photoredox-catalyzed defluoroborylation of polyfluoroarenes with NHC-BH3 has been facilely achieved at room temperature via a single-electron-transfer (SET)/radical addition pathway. This new strategy makes full use of the advantage of photoredox catalysis to generate the key boryl radical via direct activation of a B-H bond. Good functional group tolerance and high regioselectivity offer this protocol incomparable advantages in preparing a wide array of valuable polyfluoroarylboron compounds. Moreover, both computational and experimental studies were performed to illustrate the reaction mechanism.
- Chen, Kai,Chen, Xiao-Qing,Hu, Yuan-Zhuo,Xia, Peng-Ju,Xiang, Hao-Yue,Xiao, Jun-An,Yang, Hua,Ye, Zhi-Peng
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supporting information
p. 1742 - 1747
(2020/03/24)
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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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- [NiX2(NHC)2]complexes in the hydrosilylation of internal alkynes
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A number of nickel(II) dihalide complexes with small monodentate N-heterocyclic carbene ligands was synthesized and tested for their catalytic activity in the hydrosilylation of internal alkynes. The nickel(0) active species was obtained from the starting
- Berding, Joris,Van Paridon, John A.,Van Rixel, Vincent H. S.,Bouwman, Elisabeth
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experimental part
p. 2450 - 2458
(2011/08/03)
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- Superhigh purity ionic liquid
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An ionic liquid with an extremely low content of an impurity such as halogen ions which can be obtained easily at a relatively reduced cost, the ionic liquid comprising a pair of a cation K+ and an anion A- represented by the general formula (1) in which the content of an alkali metal as an impurity is 5 ppm or less and the content of a halogen ion is 1 ppm or less, the cation being preferably selected from the group represented by the following general formula (2) obtained by quarternizing a tertiary amine compound or a tertiary phosphine compound by using an acid ester represented by the following general formula (3) and then conducting salt exchange: General formula (2): General formula (3): ROY in which R1 to R4 in the formula (2) each independently represents a linear or branched alkyl group of 1 to 8 carbon atoms, X represents a hetero atom and R in the formula (3) represents a linear or branched alkyl group of 1 to 8 carbon atoms.
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- Ionic liquids as reagents and solvents in conjunction with microwave heating: Rapid synthesis of alkyl halides from alcohols and nitriles from aryl halides
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We show that using ionic liquids as reagents in conjunction with microwave heating it is possible to prepare primary alkyl halides from the corresponding alcohols rapidly. Using ionic liquids as solvents in conjunction with microwave heating it is possible to prepare aryl nitriles from the corresponding aryl bromides or iodides. The scope and limitations of using microwave-promotion as a tool in these reactions is discussed.
- Leadbeater, Nicholas E.,Torenius, Hanna M.,Tye, Heather
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p. 2253 - 2258
(2007/10/03)
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