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排序方式: 共有1313条查询结果,搜索用时 228 毫秒
1.
Junko Hirota Dr. Kazuteru Usui Dr. Yasufumi Fuchi Masaomi Sakuma Shota Matsumoto Ryusuke Hagihara Prof. Dr. Satoru Karasawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(65):14943-14952
Water-soluble donor–acceptor-type fluorophore 15Nap-Cl having two trifluoromethyl groups and a Cl group on a 1,5-aminonaphthyridine framework was prepared. Fluorophore 15Nap-Cl showed strong solvatochromic fluorescence, and, as the solvent polarity increased, a bathochromic shift was observed accompanied by an increase in the fluorescence quantum yield. In addition, in the presence of amines such as ethylamine, diethylamine, and aniline, further considerable bathochromic shifts in the fluorescence were observed. Density functional calculations identified the source of the fluorescence behavior as exciplex formation between 15-Nap-Cl and the corresponding amine. The fluorescence behavior was exploited to fabricate a sensor that can identify various primary, secondary, and tertiary amines. 相似文献
2.
Fang Xu Longjian Xie Akira Yoneda Nicolas Guignot Andrew King Guillaume Morard 《高压研究》2020,40(2):257-266
ABSTRACTTiC-MgO composite was developed as a heating element for X-ray study in the multi-anvil high pressure apparatus. We synthesized TiC-MgO blocks (50–70 wt.% of TiC) by compression in a cold isostatic press followed by baking in a gas flow furnace. Heaters of tubular shape were manufactured from the synthesized blocks either by lathe or numerically controlled milling machine. The so-produced heating elements have been proved to generate temperatures up to 2250?K at 10?GPa, condition where classical graphite heaters are not suitable anymore due to graphite-diamond transition. These new heaters have been successfully used for in situ X-ray radiography and diffraction measurements on liquid Fe alloys, exploiting excellent X-ray transparency. 相似文献
3.
Takahiro Moriyama Daiki Mizukami Dr. Makoto Yoritate Dr. Kazuteru Usui Dr. Daisuke Takahashi Dr. Eisuke Ota Prof. Dr. Mikiko Sodeoka Prof. Dr. Tadashi Ueda Prof. Dr. Satoru Karasawa Prof. Dr. Go Hirai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(11):e202103925
Minimalist photo-reactive probes, which consist of a photo-reactive group and a tag for detection of target proteins, are useful tools in chemical biology. Although several diazirine-based and aryl azide-based minimalist probes are available, no keto-based minimalist probe has yet been reported. Here we describe minimalist probes based on a 2-thienyl-substituted α-ketoamide bearing an alkyne group on the thiophene ring. The 3-alkyne probe showed the highest photo-affinity labeling efficiency. 相似文献
4.
Ph. D. Satoru Takeshita Ph. D. Takumi Ono 《Angewandte Chemie (International ed. in English)》2023,62(41):e202306518
A new series of transparent aerogels of biopolymer-polysiloxane double networks is reported. Biopolymer aerogels have attracted much attention from green and sustainable aspects but suffered from strong hydrophilicity and difficulty to make homogeneous structures in nanoscale; these drawbacks are overcome by compositing with a polysiloxane network. Alginate-polymethylsilsesquioxane aerogel has high optical transparency, water repellency, comparable superinsulation property and improved bending flexibility compared to pure polymethylsilsesquioxane aerogel. The nanoscale homogeneity is realized by separating the crosslinking steps for two networks in a sequential protocol: condensation of siloxane bonds and metal-crosslinking of biopolymer. The crosslinking order, biopolymer-first or siloxane-first, and universality/limitation of biopolymer-crosslinker pairs are discussed to construct fundamental chemistry of double network systems for their further application potentials. 相似文献
5.
Ryo Nozawa Keitaro Yamamoto Prof. Dr. Ji‐Young Shin Prof. Dr. Satoru Hiroto Prof. Dr. Hiroshi Shinokubo 《Angewandte Chemie (International ed. in English)》2015,54(29):8454-8457
Treatment of antiaromatic nickel(II) norcorrole with potassium cyanide provided nickel(II) 3‐cyanonorcorrole with perfect regioselectivity without the help of a catalyst. The reaction of the nickel(II) norcorrole with phenol or thiophenol in the presence of a base also yielded substitution products. The antiaromatic 16π conjugation system in the norcorrole core was preserved in the functionalized products. Introduction of phenylthio groups significantly decreased the HOMO–LUMO gap and enhanced the near IR absorption property. 相似文献
6.
Naoki Yoneda Yukihiro Fukata Dr. Keisuke Asano Prof. Dr. Seijiro Matsubara 《Angewandte Chemie (International ed. in English)》2015,54(51):15497-15500
Chiral spiroketal skeletons are found as core structures in a range of bioactive compounds. These natural compounds and their analogues have attracted much attention in the field of drug discovery. However, methods for their enantioselective construction are limited, and easily available optically active spiroketals are rare. We demonstrate a novel catalytic asymmetric synthesis of spiroketal compounds that proceeds through an intramolecular hemiacetalization/oxy‐Michael addition cascade mediated by a bifunctional aminothiourea catalyst. This results in spiroketal structures through the relay formation of contiguous oxacycles, in which multipoint recognition by the catalyst through hydrogen bonding imparts high enantioselectivity. This method offers facile access to spiroketal frameworks bearing an alkyl group at the 2‐position, which are prevalent in insect pheromones. Optically active (2S,5S)‐chalcogran, a pheromone of the six‐spined spruce bark beetle, and an azide derivative could be readily synthesized from the bicyclic reaction product. 相似文献
7.
Cellulose - Given that terahertz (THz) radiation responds to intermolecular forces such as hydrogen bonds, THz time-domain spectroscopy (THz-TDS) has expanded possibilities in cellulose research.... 相似文献
8.
Keigo Kobayashi Prof. Hirokazu Kobayashi Prof. Mitsuhiko Maesato Dr. Mikihiro Hayashi Tomokazu Yamamoto Dr. Satoru Yoshioka Prof. Syo Matsumura Prof. Takeharu Sugiyama Dr. Shogo Kawaguchi Prof. Yoshiki Kubota Prof. Hiroshi Nakanishi Prof. Hiroshi Kitagawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(23):6678-6682
We report on hexagonal close-packed (hcp) palladium (Pd)–boron (B) nanocrystals (NCs) by heavy B doping into face-centered cubic (fcc) Pd NCs. Scanning transmission electron microscopy–electron energy loss spectroscopy and synchrotron powder X-ray diffraction measurements demonstrated that the B atoms are homogeneously distributed inside the hcp Pd lattice. The large paramagnetic susceptibility of Pd is significantly suppressed in Pd–B NCs in good agreement with the reduction of density of states at Fermi energy suggested by X-ray absorption near-edge structure and theoretical calculations. 相似文献
9.
Sho Inagaki Akari Sato Haruka Sato Satoru Tamura Tomikazu Kawano 《Tetrahedron letters》2017,58(52):4872-4875
A simple and efficient synthesis of 4,5-dihydro-4-oxo-3-furancarboxylates using an acylative intramolecular cyclization of sulfonium salts is described. The reaction involved the efficient formation of a mixed anhydride between a linear carboxylic acid and trifluoroacetic anhydride in the presence of N-methylimidazole, followed by the sequential conversion into a highly reactive acylammonium species in situ. This procedure is easily handled, uses readily available inexpensive reagents, and provides a variety of 2-substituted 4,5-dihydro-4-oxo-3-furancarboxylates. 相似文献
10.
Alexander A. Kaminskii Ladislav Bohatý Oliver Lux Hanjo Rhee Hans Joachim Eichler Eugen Libowitzky Reiner Kleinschrodt Hitoki Yoneda Akira Shirakawa Petra Becker 《Laser \u0026amp; Photonics Reviews》2016,10(5):814-825
Hexagonal Ca5(PO4)3F, known as natural crystal fluorapatite and oldest host‐crystal for Ln3+‐lasant ions, is presented as a Raman‐active material. High‐order Raman‐induced χ(3)‐nonlinear processes are discovered in natural crystals of fluorapatite under picosecond pumping at 1.064 μm and 0.532 μm wavelength. A multitude of Stokes and anti‐Stokes components is generated in the ultraviolet, visible and near‐infrared spectral region by stimulated Raman scattering (SRS) and Raman four‐wave mixing (FWHM), resulting in a frequency comb with a width of 520 THz. The spectral lines are identified and attributed to the ν1(Ag) vibration mode of the tetrahedral [PO4] units which is related to a Raman shift of ωSRS ≈ 965 cm−1. The first Stokes steady‐state Raman gain coefficient in the near‐infrared spectral range is estimated to be >0.38 cm·GW−1. Finally, a short review of SRS‐promoting vibration modes and observed χ(3)‐ nonlinear interactions in all known SRS‐active natural crystals (minerals) is given.