The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Francis Verpoort - One of the best experts on this subject based on the ideXlab platform.
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Alkyl Group tagged ruthenium indenylidene complexes synthesis characterization and metathesis activity
Journal of Organometallic Chemistry, 2015Co-Authors: Baoyi Yu, Fatma B Hamad, Karen Leus, A A Lyapkov, Kristof Van Hecke, Francis VerpoortAbstract:Abstract We report on the synthesis of ruthenium indenylidene catalysts [RuCl2(3-R-1-indenylidene)(PCy3)2 in which R is iso-propyl (7a), tert-butyl (7b) or cyclohexyl (7c)]. The obtained Alkyl tagged indenylidene catalysts were analyzed by means of IR, elemental analysis, NMR and single crystal X-Ray diffraction analysis. Furthermore, the catalytic performance of these new complexes was examined in different metathesis reactions: ring-closing metathesis (RCM), ring-closing ene-yne metathesis (RCEYM), ring-opening metathesis polymerization (ROMP) and cross metathesis (CM), exhibiting a comparable activity in comparison with the commercially available catalyst 3a.
Kervin O. Evans - One of the best experts on this subject based on the ideXlab platform.
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Room-temperature ionic liquid cations act as short-chain surfactants and disintegrate a phospholipid bilayer
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2006Co-Authors: Kervin O. EvansAbstract:The effect of room-temperature ionic liquids (RT-ILs) cations made of 1-Alkyl-3-methylimidazolium (Alkyl Group of C4C8) and anions (commonly found in RT-ILs) on the structural integrity of large unilamellar vesicles (LUVs) of 1,2-dielaidoylphosphocholine were studied. Vesicle integrity was determined by monitoring the release of calcein quenched by cobalt ions and vesicle size distribution after incubation in the presences of each cation or anion. Results demonstrated that the instability of a fluid bilayer increased as the length of Alkyl Group of the cation increased. LUVS were mostly stable in the presence of the anions as evidenced by continued retention of encapsulated materials. Size measurements revealed, in the case of 1-butyl-3-methylimidazolium cation (100-1500 mM), encapsulated material was released through small holes in the bilayer. However, total vesicle disruption was the release mechanism in the case of 1-hexyl or octyl-3-methylimidazolium above 200 mM. © 2005 Elsevier B.V. All rights reserved.
Richard A Bartsch - One of the best experts on this subject based on the ideXlab platform.
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influence of structural variation in room temperature ionic liquids on the selectivity and efficiency of competitive alkali metal salt extraction by a crown ether
Analytical Chemistry, 2001Co-Authors: Sangki Chun, And Sergei V Dzyuba, Richard A BartschAbstract:An improved method for the preparation of 1-Alkyl-3-methylimidazolium hexafluorophosphates provides a series of room-temperature ionic liquids (RTILs) in which the 1-Alkyl Group is varied systematically from butyl to nonyl. For competitive solvent extraction of aqueous solutions of alkali metal chlorides with solutions of dicyclohexano-18-crown-6 (DC18C6) in these RTILs, the extraction efficiency generally diminished as the length of the 1-Alkyl Group was increased. Under the same conditions, extraction of alkali metal chlorides into solutions of DC18C6 in chloroform, nitrobenzene, and 1-octanol was undetectable. The extraction selectivity order for DC18C6 in the RTILs was K+ > Rb+ > Cs+ > Na+ > Li+. As the Alkyl Group in the RTIL was elongated, the K+/Rb+ and K+/Cs+ selectivities exhibited general increases with the larger enhancement for the latter. For DC18C6 in 1-octyl-3-methylimidazolium hexafluorophosphate, the alkali metal cation extraction selectivity and efficiency were unaffected by variation of...
Cornelia Tirla - One of the best experts on this subject based on the ideXlab platform.
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first carbamates conversion to amides by simple Alkyl Group transfer from triAlkylalanes
Organic Letters, 2004Co-Authors: Laurent El Kaim, Laurence Grimaud, Yannick Perroux, Cornelia TirlaAbstract:N-Monosubstituted carbamates are cleanly converted to amides under treatment with triAlkylaluminum. This reaction involves an aluminum-assisted internal delivery of Alkyl Groups. It can be applied to new and mild protecting Group strategies for alcohols.
Hideaki Shirota - One of the best experts on this subject based on the ideXlab platform.
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microscopic study of ionic liquid h2o systems Alkyl Group dependence of 1 Alkyl 3 methylimidazolium cation
Journal of Physical Chemistry B, 2010Co-Authors: Takashi Masaki, Keiko Nishikawa, Hideaki ShirotaAbstract:We have investigated the microscopic aspects for ionic liquid−H2O systems by Raman and IR spectroscopies. Ionic liquids studied here are a series of 1-Alkyl-3-methylimidazolium cations (Alkyl Groups: ethyl, butyl, hexyl, octyl, and decyl Groups) with the anions of tetrafluoroborate and bis(trifluoromethanesulfonyl)amide. Polarities of the ionic liquid−H2O systems have also been measured by means of a solvatochromic dye, betaine 33. Vibrational bands of the anions shift to the higher frequency with the higher water content. We have also found that the magnitude of the frequency shifts of the anions’ vibrational modes by adding water becomes smaller with the longer Alkyl Group of cation. From the comparison of the vibrational spectroscopic result with the result of the solvatochromic experiment, it has become clear that the frequency shift of the vibrational modes of anions almost correlates with the polarity. On the other hand, the feature of the vibrational band of water stretching mode is not really chan...
