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991.
Anilkumar R. Kore Muthian ShanmugasundaramIrudaya Charles 《Tetrahedron letters》2012,53(27):3518-3520
An efficient synthesis of new cap analogs containing aminoallyl linkers such as m7G[5′]pppp[5′]U-aminoallyl and m27,3′OG[5′]pppp[5′]U-aminoallyl is reported. The final cap analog has been isolated with high purity (>99.8%) after ion-exchange column purification. 相似文献
992.
Optimized geometry and harmonic vibrational frequency of 2-dicyanovinyl-5-(4- ethoxyphenyl)thiophene (C16H12N2OS) are calculated at the HF/6-31++G(d,p) and B3LYP/6- 311++G(d,p) levels. Mulliken charges in the ground state are also calculated. The research shows the presence of intermolecular interaction in the title compound. The scaled harmonic vibrational frequencies have been compared with experimental FT-IR spectra. A detailed interpretation of the infrared spectra of the title compound is reported. The theoretical spectrograms for IR spectra of the title compound have been constructed. The isotropic chemical shift computed by 13C and 1H NMR analyses also shows good agreement with the experimental observations. 相似文献
993.
Fluorinated compounds are commonly used for anti-stick coating but it is difficult to inspect the coverage of the coating without expensive instruments. Herein, we demonstrated that the 5-(perfluorooctylthio)acetamidofluorescein (5-FOAF) probe can be synthesized in one step and used as a testing reagent to inspect the fluorinated coating on silica- or metal-based surfaces. 5-FOAF is composed of a perfluoroalkyl domain, which has high specific affinity towards fluorinated compounds, and a fluorophore domain, which exhibits fluorescence emission visible by naked eyes. Thus, 5-FOAF will retain on the surface coated with fluorinated compounds but not on the un-coated surface and the emitted fluorescence from the retained tags serves as a semi-quantitative measure of the fluorine coverage across the surface. For this study, silica-based or metal-based surfaces were activated by silane chemistry and then coated with fluorinated compounds. The coating procedure was judiciously optimized to achieve a homogeneous coating. 5-FOAF probe was synthesized in-house and shown to retain on the fluorinated surface 2-5 times stronger than the bare surface. Moreover, by studying the retention on a non-fluoro hydrophobic substrate made of polydimethylsiloxane, the affinity of 5-FOAF with the fluorinated coating was confirmed to be specific and distinguishable from nonspecific hydrophobic interaction. In conclusion, we synthesized a novel chemical, 5-FOAF, and demonstrated its usefulness as a simple testing reagent for fluorinated coatings. 相似文献
994.
A new zinc coordination polymer, [Zn(L)(bpp)·H2O]n, was synthesized using 5-dimethylamino-isophthalic acid (H2L) and 1,3-bis(4-pyridyl)propane (bpp) as organic linkers. In the complex, adjacent Zn2+ ions are linked by L2? anions to form a one-dimensional (1D) [ZnL]n chain. Then bpp ligands expand the 1D chains into a corrugated two-dimensional (2D) layer network by linking neighboring Zn2+ ions. These adjacent layers are further stacked together by direct C?H···π supramolecular interactions, generating a three-dimensional (3D) supramolecular structure. From the viewpoint of topology, the 2D network can be rationalized to a uninodal four-connected non-interpenetrated sql/Shubnikov tetragonal plane net with {44.62} topology. Moreover, the solid state properties such as thermogravimetric analysis and luminescence were also investigated. 相似文献
995.
Hidenori Kinoshita Kazuki Yaguchi Takayuki Tohjima Katsukiyo Miura 《Tetrahedron letters》2017,58(16):1607-1610
The diisobutylaluminum hydride (DIBAL-H)-promoted benzocyclization, recently developed by this group, was adopted for the synthesis of a natural product containing a 9,10-dihydrophenanthrene skeleton to demonstrate its synthetic utility. One of the extracts from the roots of Salvia hydrangea DC. ex Bentham (Lamiaceae), a 20-norabietane derivative, was selected as the target molecule. The key step forming the 9,10-dihydrophenanthrene skeleton was achieved by the DIBAL-H-promoted cyclization of a silylated 1,3-dien-5-yne easily accessible from a substituted α-tetralone. 相似文献
996.
997.
ZSM-5/KIT-1 composites were synthesized using an ionic liquid as a template. The structures and morphologies of as-obtained products were characterized using an infrared spectroscopy, X-ray diffractometer, N2 adsorption/desorption, scanning electron microscopy and transmission electron microscopy. The resultant zeolites show a fully crystalline microporous MFI zeolite framework and a three-dimensional network of short worm-like channels. Mesopores and microspores of 4.2 and 0.8 nm in diameter coexist in the zeolite composites. Moreover, the ratio of ZSM-5 and KIT-1 could be simply adjusted by controlling the pre-crystalline time. We believe that the strategy for fabricating ZSM-5/KIT-1 through a simple method could potentially promote the large-scale production of zeolite composites. 相似文献
998.
999.
Saleh Abdel-Mgeed Ahmed 《Tetrahedron letters》2010,51(4):730-733
Eight new photochromic dihydro 5-azaindolizines (DHAIs) linked with 2,5-diaryl-1,3,4-oxadiazole (OXD) derivatives containing terminal ethynes and butadiyne substituents on the fluorene part of the DHAI skeleton are synthesized via palladium-mediated coupling reaction pathways. Irradiation of the DHAI-OXD derivatives with polychromatic light affords red- and green-colored betaines. 相似文献
1000.
Variable angle spectroscopic ellipsometry of very thin T2O5 layers on Si and the previously published appropriate algorithm for data interpretation have been successfully applied in terms of accurate characterization of very thin T2O5/Si systems. The simulation procedure following a simple three and four layered model was used assuming an existence of inhomogeneous interfacial layers. Quantitative determination of the thicknesses and composition identification were achieved, both for the top T2O5 layer and for an interfacial layer. The constituents in the interfacial layer and its depth profiles were recognized. 相似文献