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221.
The reaction of a trinuclear rhenium sulfide cluster compound Re3S7Cl7 with dimethylphenylphosphine and CuX2 (X = Cl or Br) or CuX (X = Cl, Br, or I) formed tetranuclear cluster complexes [(Ph3P)2N][Re3(CuX)(mu3-S)4Cl6(PMe2Ph)3] (X = Cl, Br, or I). Their solutions have the characteristic intense blue color with visible spectral bands near 600 nm. Single-crystal X-ray structures show that three mu-S atoms in the intermediate trinuclear rhenium complex coordinate to a copper atom, forming elongated tetrahedral structures in which Re-Cu bonding interaction is negligible (Re-Cu distances are 3.50 to approximately 3.54 A as compared with Re-Re distances ranging from 2.69 to 2.81 A). 相似文献
222.
Tsubaki K Tanaka H Takaishi K Miura M Morikawa H Furuta T Tanaka K Fuji K Sasamori T Tokitoh N Kawabata T 《The Journal of organic chemistry》2006,71(17):6579-6587
The oxidative homocoupling of optically active binaphthalenes 1a-d with a stoichiometric amount of CuCl2 and amines afforded quaternaphthalenes 2a-d in up to 93% de. The high diastereoselectivities were achieved through three different pathways (epimerization of the axis together with diastereoselective crystallization, thermodynamic, and kinetic control pathways). The type of side chains on the naphthalene influenced which pathway dominates. Three pathways were applicable to octinaphthalenes (8a-d) and hexadecanaphthalene 10a with 46-99% de. The absolute configuration of the newly formed axial bond was determined by (1) X-ray crystallographic analysis, (2) transformation to known compounds 15 and 16, (3) CD spectra of oligonaphthalenes with two pyrene rings as exciton parts, and (4) the shift values in 13C NMR spectra of 13C-enriched derivatives 29-31 toward chiral shift reagent Eu(+tfc)3. 相似文献
223.
Tetsu Ito Takehiko Tawara Hiroshi Yamaguchi Mineo Ueki Kouta Tateno Satoshi Mitsugi Hideki Gotoh Eiichi Kuramochi Masaya Notomi 《Photonics and Nanostructures》2006,4(2):89-93
We fabricated photonic-crystal (PhC) microcavities tuned to GaAs quantum dots (QDs) formed by interface fluctuation for the first time and observed the spontaneous emission enhancement in a weak coupling regime. A QD is a very thin GaAs quantum well (QW), and its interface steps exhibit quantum dot-like behavior. The emission intensity from the PhC cavity was stronger than that from the area where no PhC pattern was fabricated and the overall shape of the photoluminescence (PL) agreed with the cavity mode calculated with the three-dimensional (3D) finite-difference time domain (FDTD) method. The spontaneous emission enhancement factor was 10. 相似文献
224.
A blind deconvolution method using the concept of subband filter banks has been proposed. This method makes possible the speedy
convergence of solution, due to estimation of supports of the reconstructed images by a deconvolution in the lower layer.
We apply the method to blind deconvolution by a simulated annealing algorithm and confirm its usefulness.
Presented at 1996 International Topical Meeting on Optical Computing (OC’96), April 21–25, Sendai, Japan. 相似文献
225.
Masatoshi Maeki Yuki Teshima Saori Yoshizuka Dr. Hiroshi Yamaguchi Dr. Kenichi Yamashita Prof. Masaya Miyazaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(4):1049-1056
Herein, we demonstrate the potential of droplet‐based microfluidics for controlling protein crystallization and generating single‐protein crystals. We estimated the critical droplet size for obtaining a single crystal within a microdroplet and investigated the crystallization of four model proteins to confirm the effect of protein molecular diffusion on crystallization. A single crystal was obtained in microdroplets smaller than the critical size by using droplet‐based microfluidics. In the case of thaumatin crystallization, a single thaumatin crystal was obtained in a 200 μm droplet even with high supersaturation. In the case of ferritin crystallization, the nucleation profile of ferritin crystals had a wider distribution than the nucleation profiles of lysozyme, thaumatin, and glucose isomerase crystallization. We found that the droplet‐based microfluidic approach was able to control the nucleation of a protein by providing control over the crystallization conditions and the droplet size, and that the diffusion of protein molecules is a significant factor in controlling the nucleation of protein crystals in droplet‐based microfluidics. 相似文献
226.
Stereoselective CH Borylations of Cyclopropanes and Cyclobutanes with Silica‐Supported Monophosphane–Ir Catalysts 下载免费PDF全文
Ryo Murakami Kiyoshi Tsunoda Dr. Tomohiro Iwai Prof. Dr. Masaya Sawamura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(41):13127-13131
Heteroatom‐directed C?H borylation of cyclopropanes and cyclobutanes was achieved with silica‐supported monophosphane–Ir catalysts. Borylation occurred at the C?H bonds located γ to the directing N or O atoms with exceptional cis stereoselectivity relative to the directing groups. This protocol was applied to the borylation of a tertiary C?H bond of a ring‐fused cyclopropane. 相似文献
227.
Takaoki Ishii Ryo Watanabe Toshimitsu Moriya Prof. Dr. Hirohisa Ohmiya Prof. Dr. Seiji Mori Prof. Dr. Masaya Sawamura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(40):13547-13553
Catalyst–substrate hydrogen bonds in artificial catalysts usually occur in aprotic solvents, but not in protic solvents, in contrast to enzymatic catalysis. We report a case in which ligand–substrate hydrogen‐bonding interactions cooperate with a transition‐metal center in alcoholic solvents for enantioselective catalysis. Copper(I) complexes with prolinol‐based hydroxy amino phosphane chiral ligands catalytically promoted the direct alkynylation of aldehydes with terminal alkynes in alcoholic solvents to afford nonracemic secondary propargylic alcohols with high enantioselectivities. Quantum‐mechanical calculations of enantiodiscriminating transition states show the occurrence of a nonclassical sp3‐C? H???O hydrogen bond as a secondary interaction between the ligand and substrate, which results in highly directional catalyst–substrate two‐point hydrogen bonding. 相似文献
228.
Mine Shinya Lionet Zakary Shigemitsu Haruka Toyao Takashi Kim Tae-Ho Horiuchi Yu Lee Soo Wohn Matsuoka Masaya 《Research on Chemical Intermediates》2020,46(3):2003-2015
Research on Chemical Intermediates - This work spotlights the facile method to deposit cobalt oxide (CoOx) nanoparticles as a cocatalyst on Fe-MOF-bpdc to enhance its photocatalytic activity for... 相似文献
229.
Takashi Toyao Masayuki Minakata Kazushi Iyatani Afshin Ebrahimi Po-Chou Chen Chung-Bo Tsai Yu Horiuchi Masaya Matsuoka Masakazu Anpo 《Research on Chemical Intermediates》2013,39(1):415-424
A visible-light-responsive TiO2 thin film (Vis-TiO2), possessing a unique columnar structure oriented perpendicular to the substrate, has been prepared by using a radio-frequency magnetron sputtering deposition method. The unique TiO2 thin film was used as a key component of N719 dye-sensitized solar cells (DSSCs). The rough morphology caused by the columnar structure leads to enhanced photovoltaic performances of these DSSCs as a consequence of increased amounts of adsorbed dyes and facilitated diffusion of the electrolyte into Vis-TiO2 film. Additionally, photovoltaic performances of the DSSCs were found to depend strongly on the thickness of the Vis-TiO2 film, which can be readily controlled by adjusting the sputtering time conducted for deposition. Consequently, a solar-to-electric energy conversion efficiency of 2.6 % under AM 1.5 illumination was observed for an optimally performing DSSC that has a Vis-TiO2 film thickness of 6.9 μm, prepared by employing a sputtering time of 700 min. 相似文献
230.