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51.
An amphiphilic tetrathiafulvalene molecule can gelate a variety of organic solvents in view of multiple intermolecular interactions, especially in polar solvent with the formation of highly-ordered columnar structures. The formation of mixed-valence states shows the semiconductive behaviors with the conductivity of 10-4 S/cm, as promising candidates for organic electronics. 相似文献
52.
We have investigated the chiral adsorption configurations of styrene on Ge(100) using scanning tunneling microscopy at 300 K. The chemisorbed styrene on a single Ge dimer reduces the symmetry of the molecule, which produces a chiral center, and leads to the (S) or (R) chiral on-top configuration. We have found that the dimeric adsorption of styrene induced by the Ge surface dimer structure forms the enantiomeric and diastereomeric paired end-bridge configurations. We determine the absolute chirality of adsorbed styrene on Ge(100) and demonstrate a novel method for the achiral molecule to produce dimeric enantiomers and diastereomers attached to the semiconductor surface. 相似文献
53.
Silver ions dissolved in a polymer matrix are additionally coordinated by carbonyl oxygens of asparagines and their counter anions interact with cationic sites, resulting in the enhanced activity of the silver ion as an olefin carrier for facilitated olefin transport. 相似文献
54.
55.
Won Sick Woo Sam Sik Kang Otto Seligmann V. Mohan Chari Hildebert Wagner 《Tetrahedron letters》1980,21(44):4255-4258
From the seeds of Phytolacca americana two new lignans, Americanin B and D, have been isolated and their structures elucidated mainly by spectroscopic methods 相似文献
56.
Sang Chul Shim Chil Hoon Doh Tae Jeong Kim Hak Ki Lee Ki Doo Kim 《Journal of heterocyclic chemistry》1988,25(5):1383-1385
Ethanolic tetracarbonylhydridoferrate combined with adipaldehyde is very efficient for the selective transformation of an amino group into perhydroazepine. A large variety of both aliphatic and aromatic amines react with adipaldehyde in the presence of tetracarbonylhydridoferrate at room temperature and carbon monoxide to give the corresponding N-alkyl- and N-arylperhydroazepines in good to excellent yields. 相似文献
57.
Kang MS Kim JH Kim YJ Won J Park NG Kang YS 《Chemical communications (Cambridge, England)》2005,(7):889-891
The ionic conductivity of polymer electrolytes and their interfacial contact with dye-attached TiO2 particles were enhanced markedly by the addition of amorphous oligomer into polymer electrolytes, resulting in very high overall energy conversion efficiency. 相似文献
58.
Jae Ha Kim Young Tae Jeong Seong Ihl Woo 《Journal of polymer science. Part A, Polymer chemistry》1994,32(15):2979-2987
Highly active catalysts for copolymerization have been prepared by the precipitation of MgCl2/ToCl4 complex with or without high surface area silica. Copolymerization of ethylene and 1-butene has been tested by using the prepared catalysts at various concentrations of 1-butene. The catalytic activities are 20–80 kg/g Ti h. The rate of copolymerization is strongly affected by the addition of 1-butene. The decay rate of copolymerization is first order with respect to time. Analyses of copolymers with solvent extraction, DSC, IR, XRD, and NMR were performed. Ethylene reactivity ratio (k11) for TiCl4/MgCl2/THF catalyst is calculated to be about 26 by NMR spectrum. © 1994 John Wiley & Sons, Inc. 相似文献
59.
Pyun DK Kim BJ Jung HJ Kim JH Lee JS Lee WK Lee CH 《Chemical & pharmaceutical bulletin》2002,50(3):415-418
A new series of 1beta-methylcarbapenems 1a-d bearing 5-methyl-4-mercaptopyrrolidinone rings has been prepared and evaluated for in vitro antibacterial activity and pharmacokinetic parameters. Most compounds showed excellent antibacterial activity and high stability to dehydropeptidase-1. We have synthesized optically active 5-methyl-4-hydroxypyrrolidinones from enantiomerically pure aziridine esters. 相似文献
60.
Regio- and stereoselective iodinative cleavage of 2′,3′-anhydropurine nucleosides was achieved with samarium diiodide and ethyl bromoacetate to produce the corresponding 3′-iodopurine nucleosides, which were then converted to 3′-deoxypurine nucleosides including the natural product cordycepin. 相似文献