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301.
Seiji?TsuzukiEmail author Tadafumi?Uchimaru Masuhiro?Mikami 《Theoretical chemistry accounts》2012,131(3):1192
The interaction energy potentials for six orientations of the fucose–water complex were calculated for evaluating the magnitude
of the CH/O interactions in the complex. The calculations show that the C–H bonds of the nonpolar surface of fucose prefer
to have contact with the oxygen atom of the water. The substantial attraction exists between the C–H bonds of fucose and water.
The interaction energy calculated for the fucose–water complex at the MP2/aug-cc-pVTZ level is −2.55 kcal/mol. The CH/O interactions
in the fucose–water complex are significantly larger than those in the cyclohexane–water complex (−1.13 kcal/mol), which shows
that the oxygen atoms of fucose enhance the CH/O interactions. The electrostatic and dispersion interactions are responsible
for the attraction in the CH/O interactions in the fucose–water complex, while the electrostatic contributions to the attraction
in the CH/O interactions in the cyclohexane–water complex is small. The DFT-SAPT calculations also show that the electrostatic
interactions are responsible for the larger attraction in the fucose–water complex. These results suggest that the nature
of the CH/O interactions between carbohydrate and water is significantly different from that of the CH/O interactions between
saturated hydrocarbon and water. 相似文献
302.
A highly enantioselective alkynylation catalyzed by the dicationic (S)-BINAP-Pd complex with a variety of alkynylsilanes and trifluoropyruvate is described. The catalytic reaction is applicable to highly enantioselective addition of polyyne to trifluoropyruvate to construct α-trifluoromethyl-substituted tertiary alcohols as enantiomerically enriched forms. The alkynyl products can be converted into a chiral allene bearing a trifluoromethyl group. 相似文献
303.
The difficulty as well as the significance of the direct generation of metal enolates of alpha-CF(3) ketones cannot be easily understood by chemists unfamiliar with F. In sharp contrast to the sunny side of non-F, hydrocarbon chemistry, F chemistry has long been overshadowed. Metal enolates of carbonyl compounds are synthetically important in C-C bond-forming reactions. However, the metal enolates of fluorinated carbonyl compounds have been severely limited to alpha-F metal enolates. Alpha-CF(3) metal enolates have generally been recognized as unstable and difficult to prepare because of the facile beta-M-F elimination. However, we have developed a direct generation and synthetic application of alpha-CF(3) metal enolates. Therefore, the present results regarding the direct generation and synthetic use of metal enolates of alpha-CF(3) ketones might be recognized as a real breakthrough for the general use of metal enolates in F chemistry. 相似文献
304.
Sang-Hwui Hong Takashi Sato Makoto Mikami Masahito Uchikoshi Kouji Mimura Yoshihiko Masa Minoru Isshiki 《Journal of Crystal Growth》2009,311(13):3451-3454
Zinc oxide (ZnO) single crystal was grown, for the first time, by the self-flux method using a high-purity zinc solvent saturated with oxygen. ZnO crystals were successfully grown in the solvent by moving a growing crystal slowly, at about 17 mm/day along a temperature gradient (1.5 °C/mm) in a furnace, from 1050 to 500 °C. Hexagonal single crystals 1–3 mm in length and 0.5–1 mm in thickness were obtained. Energy-dispersive X-ray diffraction, secondary ion mass spectrometry, and photoluminescence confirmed that the purity and crystallinity of the ZnO crystals grown in this work were high. 相似文献
305.
Masato Mikami Yoshimi Mizuta Yuki Tsuchida Naoya Kojima 《Proceedings of the Combustion Institute》2009,32(2):2223-2230
An experimental study was performed on the combustion of lean-premixed spays in a counterflow. n-Decane was used as a liquid fuel with low volatility. The flame structure and stabilization were discussed based on the flame-spread mechanism of a droplet array with a low-volatility fuel. The spray flame consisted of a blue region and a yellow luminous region. The flame spread among droplets and group-flame formation through the droplet interaction were observed on the premixed spray side, while envelope flames were also observed on the opposing airflow side. The blue-flame region consisted of premixed flames propagating in the mixture layer around each droplet, the envelope diffusion flames around each droplet, the lower parts of the group diffusion flame surrounding each droplet cluster, and the envelope flame around droplets passing through the group flame. The flame was stabilized within a specific range of the mean droplet diameter via a balance between the droplet velocity and the flame-spread rate of the premixed spray. 相似文献
306.
Mikami Hirasawa Koya Shimokawa 《Proceedings of the American Mathematical Society》2000,128(11):3445-3451
In this article we show no Dehn surgery on nontrivial strongly invertible knots can yield the lens space for any integer . In order to do that, we determine band attaches to -torus links producing the trivial knot.
307.
Koichi Mikami Masahiro Yamanaka Md. Nazrul Islam Kenichi Kudo Nobuko Seino Masaki Shinoda 《Tetrahedron》2003,59(52):10593-10597
‘Fluorous nanoflow’ system is extremely effective for the lanthanide bis(perfluorooctanesulfonyl)amide-catalyzed Mukaiyama aldol reaction with dramatic increase in the reaction rate by the continuously controlled nano feeder. Thus, the acceleration of the aldol reaction was achieved even in the lowest concentration (<0.0001 M) of the lanthanide fluorous catalyst and, hence, the reaction completed within seconds as a bi-phase contact time in the micro cell. 相似文献
308.
Hiroshi MatsuzawaKoichi Mikami 《Tetrahedron letters》2003,44(33):6227-6230
Efficient enantiomeric resolution of racemates is performed by introduction of fluorous tags using β-cyclodextrin columns. Selection of appropriate length of tag and mobile phase leads to an efficient resolution of racemates (fluorinated O-acetylmandelate and ibuprofen amide) by those columns. 相似文献
309.
The radical trifluoromethylation of ketone titanium ate enolates gave alpha-CF3 ketones in good yields. The use of excess amount of LDA and Ti(OiPr)4 in the preparation of titanium ate enolates is the key to the efficient radical trifluoromethylation. [reaction: see text] 相似文献
310.
Ishikawa H Shimanuki Y Sugiyama M Tajima Y Kira M Mikami N 《Journal of the American Chemical Society》2002,124(21):6220-6230
To investigate the intramolecular charge-transfer (ICT) process of (p-cyanophenyl)pentamethyldisilane (CPDS), laser-induced fluorescence, dispersed fluorescence, and two-color resonance enhanced two-photon ionization spectra were measured in a jet-cooled isolated condition. Dual fluorescence of CPDS was observed from a ground vibrational level in the locally excited pipi state. Similar to an emission from the charge-transfer (CT) state in solution, one of the dual emissions of the isolated molecule in the jet was assigned as the CT emission. A significant vibrational dependence on the ICT process was found as exciting vibronic levels of the molecule. It was identified that the promoting mode of the ICT process is a torsional motion of the disilanyl group with respect to the phenyl ring. It was also revealed that an effective appearance energy of the CPDS cation via the CT state is much lower than that via the locally excited pipi state suggesting that the electronic configuration of the CT state is similar to that of the cation. On the basis of an electronic configuration of the cationic state, that of the CT state was suggested to be of the (sigma(Si)(-)(Si), 2ppi) type. 相似文献