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51.
A new approach to isoprostanes and neuroprostanes featuring cis-dialkyl stereochemistry at the cyclopentane ring has been developed by employing an intramolecular cross-coupling reaction of an alkyl iodide and a tethered alkenylsiloxane for stereoselective installation of a functionalized omega-side chain. 相似文献
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53.
We report a nanoscale lipid membrane-based sensor of conjugated polydiacetylene (PDA) vesicles for fluorescence detection of organic amines. The vesicle sensor was constructed by incorporation of a BODIPY fluorescent dye into the PDA vesicles. The fluorescent properties of the resulting vesicles can be manipulated by adjusting lipid components, and are controlled by environmental and solution conditions. The fluorescence of the BODIPY dye was significantly quenched in the polymerization of diacetylene lipid vesicles by a UV irradiation process. However, it was sufficiently recovered by external stimuli such as a hike of solution pH. The fluorescence recovery process was reversible, and a decrease in solution pH resulted in repeated quenching. The reported system transforms an external stimulus into a large fluorescence intensity change, demonstrating great potential in developing new signal reporting method for biosensor design. The quench-recovery phenomenon of the BODIPY-PDA is believed to be related to the energy transfer between the dye and the PDA conjugate backbone. The vesicle sensor was applied for detecting an organic amine, triethylamine (TEA) and a large linear relationship was obtained between the increase in fluorescence intensity and the concentrations of TEA. The detection limit of TEA by vesicle sensors using fluorescence recovery was found to be 10 μM. 相似文献
54.
OUH体系的结构和分析势能函数 总被引:3,自引:0,他引:3
采用密度泛涵B3LYP方法优化出了OUH分子的各种结构,确定了最稳定构型和离解能,以及它们的谐性力常数,并导出双原子分子UH,UO的Murrell-Sorbie势能函数及其光谱数据。采用多体项展式方法,导出OUH(X^4A')基态分子的分析势能函数,获得OUH(X^4A')体系的势能面,考察了这个势能函数的基本性质,正确地复现出OUH分子的平衡结构特征,结果表明:U+OH,O+UH,H+UO的反应均为无阈能的放热能反应。为进一步探讨OUH体系的反应动力学过程打下了基础。 相似文献
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56.
Lanthanum complex supported by the heterocyclic Schiff-base ligand of N-(2-pyridyl)-3,5-di-tert-butyl-salicylaldimine was prepared and employed for the ring-opening polymerization(ROP)ofε-caprolactone(ε-CL).The polymers obtained with this initiator showed a unimodal molecular weight distribution implied that only one active species was present.Mechanism study revealed that the polymerization proceeds via acyl-oxygen bond cleavage. 相似文献
57.
Sheng‐Xiong Huang Xun Liao Quan‐Jiang Nie Li‐Sheng Ding Shu‐Lin Peng 《Helvetica chimica acta》2004,87(3):598-604
Three new phenyl glycosides, scrophenoside A ( 1 ), B ( 2 ), and C ( 3 ), and two new phenylethyl glycosides, scroside D ( 4 ) and scroside E ( 5 ), were isolated from the stem of Picrorhiza scrophulariiflora Pennell (Scrophularlaceae), besides five known compounds. On the basis of spectroscopic evidence, the structures of the new compounds were elucidated as 4‐acetyl‐2‐methoxyphenyl 6‐O‐[4‐(β‐D ‐glucopyranosyloxy)vanilloyl]‐β‐D ‐glucopyranoside ( 1 ), 4‐acetylphenyl 6‐O‐[(E)‐p‐coumaroyl]‐β‐D ‐glucopyranoside ( 2 ), 4‐[(1R)‐ and (1S)‐1‐hydroxyethyl]‐2‐methoxyphenyl β‐D ‐glucopyranoside ( 3a and 3b , resp.), 2‐(3,4‐dihydroxyphenyl)ethyl O‐β‐D ‐glucopyranosyl‐(1→3)‐4‐O‐[(E)‐feruloyl]‐β‐D ‐glucopyranoside ( 4 ), and 2‐(3,4‐dihydroxyphenyl)ethyl O‐β‐D ‐glucopyranosyl‐(1→3)‐6‐O‐[(E)‐feruloyl]‐β‐D ‐glucopyranoside ( 5 ). 相似文献
58.
Xiao‐Yuan Wu Quan‐Guo Zhai Li‐Juan Chen Can‐Zhong Lu 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(6):m261-m263
The title complex, poly[di‐μ3‐oxo‐hepta‐μ2‐oxo‐tetraoxobis(1,10‐phenanthroline)‐μ4‐terephthalato‐dicopper(II)tetramolybdate(VI)], [Cu2Mo4(C8H4O4)O13(C12H8N2)2], represents a novel two‐dimensional copper–molybdate compound with mixed ligands. Tetranuclear molybdenum oxide clusters are joined through corner‐sharing into a ribbon‐like chain, with [Cu(phen)]2+ (phen is 1,10‐phenanthroline) complexes grafted onto either side. The terephthalate ligand lies about an inversion centre and links these chains to form a layer via Cu—O and Mo—O bonds. Face‐to‐face π–π stacking interactions between adjacent phen ligands stabilize the structure. 相似文献
59.
Four new 28‐noroleanane‐derived spirocyclic triterpenoids, compounds 1 – 4 , were isolated from the rhizomes of Phlomis umbrosa. Their structures were elucidated on the basis of 1D‐ and 2D‐NMR analyses, in combination with high‐resolution MS experiments. 相似文献
60.
A New Synthetic Route to 12-Oxo-1, 15-pentadecanlactam 总被引:1,自引:0,他引:1
JiaXingHUANG XiaoMeiLIANG DaoQuanWANG 《中国化学快报》2004,15(2):169-170
12-Oxo-1,15-pentadecanlactam 7 was synthesized from cyclododecanone with a totalyield of 36% in a seven-step reaction. The azide 5 to 12-nitro-1,15-pentadecanlactam 6 is the key step featured by direct ring expansion. 相似文献