- Anisotropic, Organic Ionic Plastic Crystal Mesophases from Persubstituted Imidazolium Pentacyanocyclopentadienide Salts
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We describe the synthesis, supramolecular organization, and thermal characteristics of an unprecedented family of symmetric 1,2,3,4,5-pentaalkylimidazolium ([(Cn)5im]+) salts equipped with halide, nitrate, or pentacyanocyclopentadienide ([Cp(CN)5]-) counterions. Salts containing relatively small anions were obtained as low-melting solids, whereas those with [Cp(CN)5]- anions were found to be ionic liquids even below room temperature. A permethylated derivative, [(C1)5im][Cp(CN)5], proved to be exceptional. Upon heating, the salt self-organized into a new type of organic ionic plastic crystal (OIPC) mesophase, which was termed Mhex and whose anisotropic structure featured hexagonally ordered, rotating anionic stacks positioned within a continuum composed of disordered cations. The structure of the mesophase resembles that of classical columnar liquid-crystalline phases, despite the absence of long, flexible chains. In the Mhex phase, the cations surrounding the anionic columns effectively fulfill the role of "softening" structural constituents, much in the same way as flexible chains. The discovery of the novel mesophase, which displays a two-dimensional, and thus intrinsically anisotropic, lattice resulting from the rotation of entire ionic assemblies around a columnar axis, represents a new paradigm in the field of OIPCs. Relatively high ionic conductivities were measured in the Mhex phase, particularly after doping with the corresponding sodium salt, Na[Cp(CN)5], demonstrating the materials' potential for use in electrochemical applications such as sodium-ion batteries.
- Goossens, Karel,Rakers, Lena,Heinrich, Beno?t,Ahumada, Guillermo,Ichikawa, Takahiro,Donnio, Bertrand,Shin, Tae Joo,Bielawski, Christopher W.,Glorius, Frank
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p. 9593 - 9603
(2019/12/24)
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- A Remarkably Simple Class of Imidazolium-Based Lipids and Their Biological Properties
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A series of imidazolium salts bearing two alkyl chains in the backbone of the imidazolium core were synthesized, resembling the structure of lipids. Their antibacterial activity and cytotoxicity were evaluated using Gram-positive and Gram-negative bacteria and eukaryotic cell lines including tumor cells. It is shown that the length of alkyl chains in the backbone is vital for the antibiofilm activities of these lipid-mimicking components. In addition to their biological activity, their surface activity and their membrane interactions are shown by film balance and quartz crystal microbalance (QCM) measurements. The structure-activity relationship indicates that the distinctive chemical structure contributes considerably to the biological activities of this novel class of lipids. Lipids! A series of imidazolium salts bearing two alkyl chains in the backbone were synthesized, resembling the structure of lipids. The biological activity resulting from their surface activity and membrane interaction are shown (see figure), which were determined by the alkyl chain length.
- Wang, Da,Richter, Christian,Rühling, Andreas,Drücker, Patrick,Siegmund, Daniel,Metzler-Nolte, Nils,Glorius, Frank,Galla, Hans-Joachim
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p. 15123 - 15126
(2015/11/02)
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- BIOFUEL PRODUCTION
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Methods, enzymes, recombinant microorganism, and microbial systems are provided for converting polysaccharides, such as those derived from biomass, into suitable monosaccharides or oligosaccharides, as well as for converting suitable monosaccharides or oligosaccharides into commodity chemicals, such as biofuels. Commodity chemicals produced by the methods described herein are also provided. Commodity chemical enriched, refinery-produced petroleum products are also provided, as well as methods for producing the same.
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- Convenient preparation of metals deposited on solid supports and their use in organic synthesis
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'High-surface alkali metals' can be conveniently prepared via deposition of corresponding metals on various supports such as sodium chloride, polyethylene, polypropylene and cross-linked polystyrene from their solutions in liquid ammonia. Alkali metals deposited on polymeric supports can be stored in form of stable suspensions in inert solvents and used for the acyloin and Dieckmann condensations and for preparation of organolithiums. Addition of the suspension of supported alkali metal to a solution of zinc chloride gave an active zinc on polymeric support, which can be used for the Reformatski and Barbier reactions.
- Majkosza, Mieczyslaw,Nieczypor, Piotr,Grela, Karol
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p. 10827 - 10836
(2007/10/03)
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- Convenient Preparation of 'High-Surface Sodium' in Liquid Ammonia: Use in the Acyloin Reaction
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'Sodium on solid support' (5-20 wt.% of Na on NaCl, glass powder, poly(ethylene) and poly(propylene)) can be conveniently prepared via low-temperature (-33°C) deposition of sodium from its solution in liquid ammonia. Use of this reagent in the acyloin reaction of carboxylic esters gave the corresponding products in good yields.
- Makosza, Mieczyslaw,Grela, Karol
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p. 267 - 268
(2007/10/03)
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- Catalytic action of azolium salts. VI. Preparation of benzoins and acyloins by condensation of aldehydes catalyzed by azolium salts
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Benzoins 4 (2-hydroxyethanones substituted with aryl groups at the 1- and 2-positions) were prepared by self-condensation of aromatic aldehydes 3 using catalytic amounts of azolium salts 1 and 2 in excellent yields. 1,3-Dimethylbenzimidazolium iodide (2) was an effective catalyst for the preparation of acyloins 6 (2-hydroxyethanones substituted with alkyl groups at the 1- and 2-positions) by self-condensation of aliphatic aldehydes 5. On the other hand, an attempt at the condensation of hexanal (5d) catalyzed by 1,3-dimethylimidazolium iodide (1) failed to yield the acyloin 6d, and instead the aldol-type condensed product 8d was obtained.
- Miyashita,Suzuki,Iwamoto,Higashino
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p. 2633 - 2635
(2007/10/02)
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- ELECTRON TRANSFER REACTIONS OF ALIPHATIC ESTERS TO THE CORRESPONDING ALIPHATIC KETONES BY LITHIUM 4,4'-DI-T-BUTYLBIPHENYL RADICAL ANION
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Sonication of some representative aliphatic esters with lithium in the presence of catalytic amounts of 4,4'-di-t-butylbiphenyl (DBB) in dry THF under N2 afforded the corresponding aliphatic ketones in good yields.Monitoring studies by GC/MS and 1H-NMR spectroscopy after quenching indicate the intermediacy of the corresponding β-ketoesters.
- Karaman, Rafik,Fry, James L.
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p. 4935 - 4938
(2007/10/02)
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