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排序方式: 共有369条查询结果,搜索用时 31 毫秒
361.
Hamura T Chuda Y Nakatsuji Y Suzuki K 《Angewandte Chemie (International ed. in English)》2012,51(14):3368-3372
A fair exchange: In the title reaction, alkynyllithium serves as an initiator for benzyne generation through an iodine-lithium exchange (see scheme; Tf=trifluoromethanesulfonyl). When performed in the presence of stoichiometric amounts of a nucleophile, the generated benzyne undergoes attack by lithio nucleophiles to generate aryllithium, which is then iodinated by iodoalkyne to give the iodoarenes 1. 相似文献
362.
Haketa Y Bando Y Takaishi K Uchiyama M Muranaka A Naito M Shibaguchi H Kawai T Maeda H 《Angewandte Chemie (International ed. in English)》2012,51(32):7967-7971
Asymmetry through ion pairing: Upon addition of chloride and bromide ions, as chiral ammonium salts, to solutions of pyrrole-based π-conjugated linear oligomers, helical structures form with asymmetric induction, which is guided by the formation of diastereomeric ion pairs with chiral counter cations. These ions pairs exhibit circular dichroism (CD) and strong circularly polarized luminescence (CPL) with g(lum) values of greater than 0.1. 相似文献
363.
Y Kado CY Lee K Lee J Müller M Moll E Spiecker P Schmuki 《Chemical communications (Cambridge, England)》2012,48(69):8685-8687
We use a highly aligned Ta(2)O(5) nanochannel structure to fabricate alkali metal ion (Na, K, Rb or Cs) doped Ta(3)N(5)via solution seeding and thermal conversion in NH(3). Under optimized conditions the resulting doped structures show a strongly enhanced visible light water splitting performance in comparison to undoped Ta(3)N(5). 相似文献
364.
Higuchi T Fujimura H Hitomi Y Arakaki T Oomori T Suzuki Y 《Photochemistry and photobiology》2010,86(6):1421-1426
Various stresses induce the formation of reactive oxygen species (ROS) in biological cells. In addition to stress-induced ROS, we studied the photochemical formation of hydroxyl radicals (˙OH), the most potent ROS, in coral tissues using phosphate buffer-extracted solutions and a simulated sunlight irradiation system. ˙OH formation was seen in extracts of both coral host and endosymbiont zooxanthellae. This study is the first to report quantitative measurements of ˙OH photoformation in coral tissue extracts. Our results indicated that whether or not coral bleaching occurred, coral tissues and symbiotic zooxanthellae have the potential to photochemically produce ˙OH under sunlight. However, no significant difference was found in the protein content-normalized formation rates of ˙OH between corals incubated under different temperatures and irradiance conditions. ˙OH formation rates were reduced by 40% by reducing the UV radiation in the illumination. It was indicated that UV radiation strongly affected ˙OH formation in coral tissue and zooxanthellae, in addition to its formation through photoinhibition processes. 相似文献
365.
Makoto Tsuboi Yuya Yomoda Hideaki Kato Yukimasa Terada Hironobu Mori 《Tetrahedron letters》2010,51(4):676-10578
The in vitro reactivity of lutein toward peroxynitrite was investigated, and the reaction products produced by scavenging with peroxynitrite were analyzed. A novel lutein-6H-1,2-oxazine (1) along with 14-s-cis-15-nitirolutein (2) and 14′-s-cis-15′-nitrolutein (3) was isolated from the products of the reaction of lutein with peroxynitrite. These results indicate that lutein is able to capture peroxynitrite and nitrogen dioxide radicals from their molecules to form oxazine or nitrocarotenoids. 相似文献
366.
Daisuke Sawada Yuya Tsukuda Hiroshi Saito Eiji Ochiai Kazuya Takenouchi 《Tetrahedron》2010,66(29):5407-5423
2α- and 2β-Substituted analogs of 14-epi-previtamin D3 were synthesized and isolated after thermal isomerization of 14-epi-vitamin D3 triene at 80 °C. The VDR binding affinity and transactivation activity of osteocalcin promoter in HOS cells were tested, and the 2α-methyl-substituted analog was found to have greater genomic activity than 14-epi-previtamin D3. We found that modification at the C2 position of the seco-steroidal skeleton afforded interesting effects for biological genomic activity for the previtamin D form as well as the natural vitamin D form. 相似文献
367.
We have evaluated the plasticizing effect of poly(butylene succinate) (PBS) and cellulose acetate butyrate (CAB). PBS and CAB were mixed with a melt-kneading machine. The tensile strength and strain at break in the case of the blend with 10% CAB in the PBS matrix were 547% and 35 MPa. It showed that CAB acted as a plasticizer for PBS. The biomass carbon ratio of the blends measured by accelerator mass spectrometry based on ASTM D6866 showed that the biomass carbon derived from a part of the CAB corresponded to the theoretical value of the polymer blend. The biodegradation of PBS with the CAB melt blend powders was evaluated by a microbial oxidative degradation analyzer under controlled compost conditions based on ISO 14855-2. PBS with 10% CAB was not degraded within 60 days due to the addition of CAB that could control the biodegradability of the PBS. 相似文献
368.
Kazuki Toyama Dr. Yuya Tanaka Prof. Dr. Michito Yoshizawa 《Angewandte Chemie (International ed. in English)》2023,62(37):e202308331
A ferrocene-based capsule is spontaneously and quantitatively formed in water by the assembly of bent amphiphiles carrying two ferrocene units. The disassembly and assembly of the new organometallic capsule, with a well-defined and highly condensed ferrocene core, are demonstrated by chemical redox stimuli in a fully reversible fashion under ambient conditions. In contrast to previously reported multiferrocene assemblies, only the present capsule efficiently encapsulates typical organic/inorganic dyes as well as electron-accepting molecules in water. As a result, unusual host-guest charge-transfer (CT) interactions, displaying relatively wide absorption bands in the visible to near-infrared region (λ=650–1350 nm), are observed upon the encapsulation of acceptors (i.e., chloranil and TCNQ). The resultant encapsulation-induced CT interactions can be released by a redox stimulus through the disassembly of the capsule. 相似文献
369.
Takahiro Sakurai Yuya Hiraoka Dr. Hisaaki Tanaka Prof. Dr. Yoshihiro Miyake Prof. Dr. Norihito Fukui Prof. Dr. Hiroshi Shinokubo 《Angewandte Chemie (International ed. in English)》2023,62(12):e202300437
NiII 3,7,13,17-tetrapyridyl-5,15-diazaporphyrin serves as a double tridentate ligand to PdII ions to provide a pincer-type bispalladium complex. Electrochemical analysis revealed that the bispalladium complex shows excellent ability to accept electrons and reversible redox properties due to the coordination of the two cationic PdII centers to the meso-nitrogen atoms. We isolated and characterized one- and two-electron reduction species of the bispalladium complex. The 20π antiaromatic nature of the two-electron reduction species was confirmed by 1H NMR spectroscopy, UV/Vis-near-IR (NIR) absorption spectra, and density functional theory (DFT) calculations. X-ray diffraction revealed highly twisted structures for the bispalladium complexes regardless of the oxidation state. 相似文献