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991.
Cover Picture: The Effect of Cholesterol on Membrane Dynamics on Different Timescales in Lipid Bilayers from Fast Field‐Cycling NMR Relaxometry Studies of Unilamellar Vesicles (ChemPhysChem 3/2014)
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Mateusz Marianski Eike Mucha Kim Greis Sooyeon Moon Alonso Pardo Carla Kirschbaum Daniel A. Thomas Gerard Meijer Gert von Helden Kerry Gilmore Peter H. Seeberger Kevin Pagel 《Angewandte Chemie (International ed. in English)》2020,59(15):6166-6171
The stereoselective formation of 1,2‐cis‐glycosidic bonds is challenging. However, 1,2‐cis‐selectivity can be induced by remote participation of C4 or C6 ester groups. Reactions involving remote participation are believed to proceed via a key ionic intermediate, the glycosyl cation. Although mechanistic pathways were postulated many years ago, the structure of the reaction intermediates remained elusive owing to their short‐lived nature. Herein, we unravel the structure of glycosyl cations involved in remote participation reactions via cryogenic vibrational spectroscopy and first principles theory. Acetyl groups at C4 ensure α‐selective galactosylations by forming a covalent bond to the anomeric carbon in dioxolenium‐type ions. Unexpectedly, also benzyl ether protecting groups can engage in remote participation and promote the stereoselective formation of 1,2‐cis‐glycosidic bonds. 相似文献
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Carla C. Johnson 《School science and mathematics》2014,114(6):257-257
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Inside Cover: Single‐Walled Carbon Nanotubes in Highly Viscous Media: A Comparison between the Dispersive Agents [BMIM][BF4], L121, and Triton X‐100 (Chem. Eur. J. 2/2016)
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Insights into the Formation and Structures of Molecular Gels by Diimidazolium Salt Gelators in Ionic Liquids or “Normal” Solvents
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Dr. Carla Rizzo Prof. Francesca D'Anna Prof. Renato Noto Mohan Zhang Prof. Richard G. Weiss 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(32):11269-11282
Insights are provided into the properties of molecular gels formed by diimidazolium salts both in “normal” solvents and ionic liquids. These materials can be interesting for applications in green and sustainable chemistry in which ionic liquids play a significant role, like catalysis and energy. In particular, two positional isomers of a diimidazolium cation have been examined with a wide range of anions for their ability to form gel phases. In particular, di‐, tri‐, and tetravalent anions bearing aliphatic or aromatic spacers were paired with the divalent cations. The properties of the organo‐ and ionogels formed have been analyzed by means of several different techniques, including calorimetry, rheology, resonance light scattering, UV/Vis absorption, polarizing optical microscopy, and powder X‐ray diffraction measurements. The investigations performed enabled us to obtain a wide range of conductive materials characterized by a high thermal stability and a low corrosiveness of the gelator (organogels) or of both gelator and solvent (ionogels). The information gained should be useful in the broader quest to identify and promote their applications. 相似文献