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51.
Keika Hattori Kazuya Yamaguchi Junichiro Yamaguchi Kenichiro Itami 《Tetrahedron》2012,68(37):7605-7612
The palladium- and copper-catalyzed C–H arylation reactions of 1H- and 2H-indazoles with haloarenes are described. A PdCl2/phen/Ag2CO3/K3PO4 catalytic system is effective for the C–H arylation of 1H- and 2H-indazoles with haloarenes, whereas a less expensive CuI/phen/LiOt-Bu catalytic system is applicable to the C–H coupling of substituted 2H-indazoles and iodoarenes. The utility of newly developed catalyst was demonstrated in the rapid synthesis of YC-1 (an antitumor agent) and YD-3 (platelet anti-aggregating agent). These new reactions represent important direct functionalization tools of indazoles, well-known bioisosteres of pharmaceutically important indole core. 相似文献
52.
53.
Arunabhiram Chutia Riadh SahnounRamesh C. Deka Zhigang ZhuHideyuki Tsuboi Hiromitsu TakabaAkira Miyamoto 《Physica B: Condensed Matter》2011,406(9):1665-1672
Based on experimental findings models of amorphous graphene related carbon materials were generated using graphene nano flakes. On the optimized structures detailed local electronic properties were investigated using density functional theory. The electrical conductivities of all these models were also estimated using an in-house program based on tight-binding method. The calculated electrical conductivity values of all the models agreed well with the trend of calculated energy gap and graphitic character. 相似文献
54.
Feroza Begum Yoshinori Namihira S. M. Abdur Razzak Shubi F. Kaijage Nguyen H. Hai Kazuya Miyagi Hiroki Higa Nianyu Zou 《Optical Review》2009,16(2):54-58
This research presents a simple index-guiding square photonic crystal fibers (SPCFs) that has a silica core surrounded by
air hole with two different diameters. It is demonstrated that the designed two-different-size hole-arrayed index-guiding
SPCFs has a ultra-flattened chromatic dispersion of 0 ± 0.9 ps/(nm·km) in a wavelength range of 1.34 to 1.61 μm and low confinement
loss of less than 10−7 dB/m in a wavelength range of 1.2 to 1.7 μm. It has also been shown that the proposed SPCFs show reasonable dispersion tolerance. 相似文献
55.
Md. Khorshed Alam Ryuji Miura Hideyuki Tsuboi Akira Endou Momoji Kubo 《Applied Surface Science》2010,257(5):1383-1389
Ceria plays an important role in catalysis, due to its ability to store and release oxygen depending on the condition present in the catalyst environment. To analyze the role of ceria in catalytic reactions, it is necessary to know the details of the interaction of ceria surface with environmentally sensitive molecules. This study was conducted using ultra accelerated quantum chemical molecular dynamics. Its purpose was to investigate the reduction process of the (1 1 1) and (1 1 0) surfaces of ceria with atomic hydrogen as well as water desorption mechanisms from the surfaces. This simulation demonstrated that when a high-energy colliding hydrogen atoms are adsorbed on the ceria, it pulls up an O atom from the ceria surfaces and results in the formation of a H2O molecule. This is the first dynamics simulation related to such reduction processes based on quantum chemistry. 相似文献
56.
Water‐ and Temperature‐Triggered Reversible Structural Transformation of Tetranuclear Cobalt(II) Cores Sandwiched by Polyoxometalates 下载免费PDF全文
Yosuke Kuriyama Dr. Yuji Kikukawa Dr. Kosuke Suzuki Dr. Kazuya Yamaguchi Prof. Dr. Noritaka Mizuno 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(12):3962-3966
Although stimuli‐responsive structural transformations of inorganic materials have attracted considerable attention because of their potential use as functional switchable materials, multinuclear metal cores frequently suffer from unexpected dissociation of metal cations and/or irreversible transformations into infinite structures. In this study, we describe the successful demonstration of the water‐ and temperature‐triggered reversible structural transformation between cubane‐ and planar‐type tetranuclear CoII cores sandwiched by polyoxometalates. The arrangements and coordination geometries of the CoII cations were interconverted by simple hydration and dehydration, resulting in the manipulation of the magnetic and optical properties of these compounds. Moreover, this system showed unique thermochromism through temperature‐dependent reversible structural interconversion. 相似文献
57.
Silviu Polosan Tahsin J. Chow Taiju Tsuboi 《Journal of Physical Organic Chemistry》2008,21(4):315-320
Electronic states and their energies are calculated for a mixed‐ligand Ir(III) compound, (5‐chloro‐8‐hydroxyquinoline) bis(2‐phenylpyridyl) iridium (called IrQ(ppy)2‐5Cl) using time‐dependent density functional theory (TDDFT) calculations and are compared with the experimental result. A good agreement is obtained between the calculated and measured absorption spectra. The d‐πQ* molecular orbital transition gives the lowest‐energy triplet state absorption band. Its energy is estimated as 1.84 eV (671 nm), which is close to the absorption band position of 1.86 eV (666 nm) observed for IrQ(ppy)2‐5Cl doped in 4,4′‐N,N′‐dicarbazole‐biphenyl (CBP) host and of 1.88 eV (660 nm) observed for IrQ(ppy)2‐5Cl doped in polystyrene (PS). The second triplet state absorption band is caused by d‐πppy transition. Its position is calculated as 2.51 eV (494 nm). The dipole moment is estimated as 3.45 D, which is lower than the dipole moment of fac‐Ir(ppy)3. This is understood by a reduced charge transfer between Ir(III) and quinoline ligand. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
58.
Optical solitary waves that propagate in a Kerr medium exhibiting a power-law nonlocal response are studied analytically. The first-principles stability analysis based on quantum field theory shows that within the whole range of the exponent (the fractal dimension) the solitary wave can be stabilized. 相似文献
59.
60.
Takahiko Ishiguro Ei-ichiro Suzuki Akiko Y. Hirakawa Masamichi Tsuboi 《Journal of Molecular Spectroscopy》1980,83(2):360-372
Raman spectra of thiourea have been observed in H2O and D2O solutions with the exciting laser beams of 514.5, 488.0, 457.9, 363.8, 325.0, and 257.3 nm. The resonance Raman excitation profile of the 729-cm?1 line has been examined in the region of the 237-nm absorption band () by use of a solvent shift of the absorption band instead of by changing the wavelength of the exciting beam. The depolarization degree of this line was measured and its overtone Raman line was also observed. On the basis of the results of these experiments, it has been concluded that the 729-cm?1 Raman line, assignable to the CS stretching vibration, derives its intensity solely from the 237-nm band when it is excited at 257.3 or 325.0 nm. On exciting in the region 363.8–514.5 nm, however, contributions of the higher-frequency bands are predominant rather than the contribution from the 237-nm band. The Raman line at 1520 cm?1 of thiourea-d4 is assignable to the NCN antisymmetric stretching vibration. From its excitation profile, its intensity has been considered to come from a vibronic coupling between the excited electronic states of the 220-nm () and the 197-nm () bands. 相似文献