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排序方式: 共有419条查询结果,搜索用时 265 毫秒
201.
202.
Amandine Cadiau Nikita Kolobov Sivaranjani Srinivasan Maarten G. Goesten Henrik Haspel Anastasiya V. Bavykina Mohamed R. Tchalala Partha Maity Andrey Goryachev Artem S. Poryvaev Mohamed Eddaoudi Matvey V. Fedin Omar F. Mohammed Jorge Gascon 《Angewandte Chemie (International ed. in English)》2020,59(32):13468-13472
The one‐step synthesis and characterization of a new and robust titanium‐based metal–organic framework, ACM‐1 , is reported. In this structure, which is based on infinite Ti?O chains and 4,4′,4′′,4′′′‐(pyrene‐1,3,6,8‐tetrayl) tetrabenzoic acid as a photosensitizer ligand, the combination of highly mobile photogenerated electrons and a strong hole localization at the organic linker results in large charge‐separation lifetimes. The suitable energies for band gap and conduction band minimum (CBM) offer great potential for a wide range of photocatalytic reactions, from hydrogen evolution to the selective oxidation of organic substrates. 相似文献
203.
Wang J Han X Saha S Xu T Rai R Zhang F Wolf YI Wolfson A Yates JR Kashina A 《Chemistry & biology》2011,18(1):121-130
Posttranslational arginylation mediated by arginyl transferase (ATE1) plays an important role in cardiovascular development, cell motility, and regulation of cytoskeleton and metabolic enzymes. This protein modification was discovered decades ago, however, the arginylation reaction and the functioning of ATE1 remained poorly understood because of the lack of good biochemical models. Here, we report the development of an in vitro arginylation system, in which ATE1 function and molecular requirements can be tested using purified recombinant ATE1 isoforms supplemented with a controlled number of components. Our results show that arginylation reaction is a self-sufficient, ATP-independent process that can affect different sites in a polypeptide and that arginyl transferases form different molecular complexes in vivo, associate with components of the translation machinery, and have distinct, partially overlapping subsets of substrates, suggesting that these enzymes play different physiological functions. 相似文献
204.
A working methodology to generate theoretical IR spectra following ab initio electronic structure methods is reported. Theoretical IR spectra of Cl(2)(?-)·nH(2)O clusters (n = 1-5) are generated as a case study. Excellent agreement between the calculated and the reported experimental IR spectra based on size-selected spectroscopy is observed. It is shown that uniform scaling of calculated harmonic frequencies of these hydrated clusters fail to produce accurate IR spectra. Two different scaling factors in two different regions of O-H stretching of solvent water molecules are needed to account for the anharmonic contribution. This observation is also true for Br(2)(?-)·nH(2)O and I(2)(?-)·nH(2)O systems. 相似文献
205.
Kundu N Maity M Chatterjee PB Teat SJ Endo A Chaudhury M 《Journal of the American Chemical Society》2011,133(50):20104-20107
Valence tautomeric compounds involving nondixolene-type ligands are rare. The triple-helicate copper(II) complex [Cu(II)(2)(L)(3)](ClO(4))(4)·3CH(3)CN (1) containing a redox-active N-heterocyclic ligand (L) has been prepared and displays VT equilibrium in solution, as established by electronic spectroscopy, electron paramagnetic resonance spectroscopy, and cyclic and differential pulse voltammetry carried out at variable temperatures. The process involves intramolecular transfer of an electron from one of the L ligands to a copper(II) center, leading to the oxidation of L to an L(?+) radical with concomitant reduction of the Cu(II) center to Cu(I), as shown by the equilibrium [Cu(II)Cu(I)L(?+)L(2)](4+) ? [Cu(II)(2)L(3)](4+). 相似文献
206.
Direct alkenylation of indoles at the 3-position with 1,3-dicarbonyl compounds under Brønsted acidic ionic liquid catalysis has been developed. The yields were excellent, and the catalyst can be reused at least six times without noticeable loss of catalytic activity. 相似文献
207.
A new highly selective colorimetric chemosensor for Co(2+) was developed based on coumarin-conjugated thiocarbanohydrazone. The ligand senses Co(2+) in solution by changing its color from light yellow to deep pink. The sensor has been used in the development of practically viable colorimetric kits and as a staining agent for Co(2+) in microorganisms. 相似文献
208.
Mane RS Ghosh S Chopade BA Reiser O Dhavale DD 《The Journal of organic chemistry》2011,76(8):2892-2895
The (8'R) epimeric carbohydrate core 2 of amipurimycin was synthesized from D-glucose derived allylic alcohol 3 in 11 steps and 13% overall yield. The key steps involve an acid-catalyzed acetonide ring opening of 9 with concomitant formation of an unprecedented pyranose ring skeleton to give 2,7-dioxabicyclo[3.2.1]octane 10. The α-orientation of the furan ring in 10 readily allows the stereoselective β-glycosylation and opening of the furanose ring that on removal of protecting groups affords the pyranosyl adenine nucleoside 2. The antifungal and anticancer activities of 2 were studied. 相似文献
209.
Sarmistha Maity A. Dhar D. Bhattacharya 《Journal of Physics and Chemistry of Solids》2011,72(6):804-809
The paper presents the fabrication and characterization of La0.65Sr0.35MnO3−δ (LSMO) polycrystalline thin films deposited directly on Si (1 0 0) substrates using pulsed laser deposition technique. Various deposition parameters like substrate temperature and oxygen partial pressure have been varied systematically to obtain stoichiometric, crack-free films with smooth surface morphology having nearly monodisperse grain size distribution. The substrate temperature variation from 600 to 800 °C had profound effects on the microstructure and topography of the deposited film, with optimum result being obtained at 700 °C. The variation of partial pressure of oxygen controls the deposition kinetics as well as the stoichiometry of the film in terms of oxygen vacancy, which influences the magnetic and electrical transport properties of the manganate films. The microstructure and crystallinity of the deposited films have been studied using X-ray diffraction, scanning electron microscopy and atomic force microscopy. A correlation between the oxygen stoichiometry and micro-structural and transport properties of the deposited films has been obtained. 相似文献
210.
Compressional waves in a magnetized plasma of arbitrary resistivity are treated with the lagrangian fluid approach. An exact nonlinear solution with a nontrivial space and time dependence is obtained with boundary conditions as in Harris' current sheet. The solution shows competition among hydrodynamic convection, magnetic field diffusion, and dispersion. This results in a collapse of density and the magnetic field in the absence of dispersion. The dispersion effects arrest the collapse of density but not of the magnetic field. A possible application is in the early stage of magnetic star formation. 相似文献