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排序方式: 共有409条查询结果,搜索用时 15 毫秒
1.
Structural Chemistry - The hydrogen bond interactions between methyl-imidazolium cation (MIM+) and fatty acid anions (CmHnCOO–, where m?=?1–6; n-3–13) of ionic liquids... 相似文献
2.
The temperature dependence of the electric quadrupole interaction frequency
l
o
, experienced by the181Ta probe occupying Hf site in the compounds Hf1-xTaxV2 has been measured for x=0.06, 0.10 and 0.20 in the temperature region between 8.5 K to 296 K. The measurements show lattice transformation in all the three compounds below 120 K. 相似文献
3.
Zirconyl chloride promoted highly efficient solid phase synthesis of amide derivatives 总被引:1,自引:0,他引:1
Cherkupally Sanjeeva Reddy Adki Nagaraj Pochampally Jalapathi 《中国化学快报》2007,18(10):1213-1217
An efficient solid phase route for the synthesis of amide derivatives by the reaction of carboxylic acids with urea in the presence of catalytic amount of zirconyl chloride under microwave irradiation conditions was described.In this way,a range of interesting amide derivatives was obtained in good to excellent yields.The catalyst was recycled with fresh reactants and it gave almost similar results without significant loss of activity up to the third run. 相似文献
4.
Subramaniam V Alves ID Salgado GF Lau PW Wysocki RJ Salamon Z Tollin G Hruby VJ Brown MF Saavedra SS 《Journal of the American Chemical Society》2005,127(15):5320-5321
Transmembrane proteins (TMPs), particularly ion channels and receptors, play key roles in transport and signal transduction. Many of these proteins are pharmacologically important and therefore targets for drug discovery. TMPs can be reconstituted in planar-supported lipid bilayers (PSLBs), which has led to development of TMP-based biosensors and biochips. However, PSLBs composed of natural lipids lack the high stability desired for many technological applications. One strategy is to use synthetic lipid monomers that can be polymerized to form robust bilayers. A key question is how lipid polymerization affects TMP structure and activity. In this study, we have examined the effects of UV polymerization of bis-Sorbylphosphatidylcholine (bis-SorbPC) on the photoactivation of reconstituted bovine rhodopsin (Rho), a model G-protein-coupled receptor. Plasmon-waveguide resonance spectroscopy (PWR) was used to compare the degree of Rho incorporation and activation in fluid and poly(lipid) PSLBs. The results show that reconstitution of Rho into a supported lipid bilayer composed only of bis-SorbPC, followed by photoinduced lipid cross-linking, does not measurably diminish protein function. 相似文献
5.
Kessel L Kalinin S Nagaraj RH Larsen M Johansson LB 《Photochemistry and photobiology》2002,76(5):549-554
The intrinsic fluorescence from the human lens on excitation in the UV region, referred to as blue lens autofluorescence, increases with age or in the presence of diabetes. The present study reveals that the relative contribution of compounds responsible for the blue autofluorescence appears to be a constant with age. Three potential candidates for the blue fluorescence were also studied with respect to fluorescence spectroscopic properties. These were argpyrimidine and pentosidine, both advanced glycation end products, and 3-hydroxykynurenine (3-OH-kynurenine), a photooxidative derivative of tryptophan. It was shown that the spectral properties of argpyrimidine and pentosidine are compatible with the observed blue fluorescence of the human lens, whereas the fluorescence from 3-OH-kynurenine is negligible. 相似文献
6.
A.A.Leslie Gunatilaka Subramaniam Sotheeswaran H.T.Badra Sriyani Eric S. Waight 《Tetrahedron letters》1982,23(29):2987-2990
Hermonionic acid and its decarboxylated product have been isolated from . 13C NMR spectral and chemical evidence indicate that hermonionic acid is 2-0-[2-(3-methylbut-2-enyl)-3-methoxy- 4-hydroxy-5-(3,7-dimethylocta-2,6-dienyl]-4-methoxy-5-(3-methylbut-2-enyl-6-hydroxybenzoic acid. The previously assigned dienone structure for this acid is incorrect. 相似文献
7.
CO(2)-expanded solvents: unique and versatile media for performing homogeneous catalytic oxidations 总被引:2,自引:0,他引:2
Wei M Musie GT Busch DH Subramaniam B 《Journal of the American Chemical Society》2002,124(11):2513-2517
The work summarized here demonstrates a new concept for exploiting dense phase CO(2), media considered to be "green" solvents, for homogeneous catalytic oxidation reactions. According to this concept, the conventional organic solvent medium used in catalytic chemical reactions is replaced substantially (up to 80 vol %) by CO(2), at moderate pressures (tens of bars), to create a continuum of CO(2)-expanded solvent media. A particular benefit is found for oxidation catalysis; the presence of CO(2) in the mixed medium increases the O(2) solubility by ca. 100 times compared to that in the neat organic solvent while the retained organic solvent serves an essential role by solubilizing the transition metal catalyst. We show that CO(2)-expanded solvents provide optimal properties for maximizing oxidation rates that are typically 1-2 orders of magnitude greater than those obtained with either the neat organic solvent or supercritical CO(2) as the reaction medium. These advantages are demonstrated with examples of homogeneous oxidations of a substituted phenol and of cyclohexene by molecular O(2) using transition metal catalysts, cobalt Schiff-base and iron porphyrin complexes, respectively, in CO(2)-expanded CH(3)CN. 相似文献
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