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1.
Joji Ohshita Ryosuke Taketsugu Yuki Nakahara Atsutaka Kunai 《Journal of organometallic chemistry》2004,689(20):3258-3264
Selective dehydrogenative coupling of di- and trihydrosilanes with alcohols catalyzed by PdCl2 or NiCl2 afforded alkoxyhydro- and dialkoxyhydrosilanes in good yield. Further treatment of the resulting alkoxyhydrosilanes with carbon tetrachloride or allyl bromide in the presence of the same catalyst led to the formation of alkoxychloro- and alkoxybromosilanes, respectively. Similar reactions of dialkoxyhydrosilanes with carbon tetrachloride afforded dialkoxychlorosilanes in good yield, although contamination of small amounts of trialkoxysilanes and alkoxydichlorosilanes was detected in the products. Selective substitution of the alkoxyhalosilanes with nucleophiles is also reported. 相似文献
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Hiroto Yoshida Yasuhito YamaryoJoji Ohshita Atsutaka Kunai 《Tetrahedron letters》2003,44(8):1541-1544
Base-free oxidative homocoupling reaction of arylboronic esters has been found to proceed using a catalytic amount of a palladium-1,3-bis(diphenylphosphino)propane (DPPP) complex under an oxygen atmosphere, affording a variety of biaryls in modest to excellent yields. Even arylboronic esters bearing a base-sensitive functional group are applicable to the reaction. 相似文献
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Y. Harima D.-H. Kim Y. Tsutitori X. Jiang R. Patil Y. Ooyama J. Ohshita A. Kunai 《Chemical physics letters》2006,420(4-6):387-390
Carrier mobilities in thin films of copolymers with repeat units consisting of oligothiophenes bridged by Si atoms are measured over a range of doping levels, where the numbers of thienylenes in the repeat unit are 7, 8, 10, 12, and 14. The mobilities for these polymer films increased with the increase in doping level and the mobility enhancement followed an increasing order of the π-conjugation length. The magnitude of the mobility increase for the Si polymer comprising 14 thiophene units reached ca. 104, implying that this π-conjugation length is almost sufficient to reproduce transport properties of polythiophenes. 相似文献
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Joji Ohshita Takahiro Inoue Taisuke Uemura Toshiyuki Iida Atsutaka Kunai 《Silicon Chemistry》2003,2(3-4):147-149
Compounds having two benzocrown ether units bridged by an organosilicon bridge were prepared by the reactions of lithiated benzocrown derivatives with dichloromono- and disilanes in THF, and the ionochromic effects on their optical properties were studied. Of those, disilanylene-bridged benzocrown ethers exhibited clear ionochromism in the emission spectra and the intensity of the original emission band at about 320 nm decreased and a new broad band centered at 400 nm appeared, when selected alkali or alkali-earth metal ions were added into the acetonitrile solutions. In contrast to this, no significant changes were observed in the UV absorption spectra on addition of the metal ions. 相似文献
6.
Yoshida H Mimura Y Ohshita J Kunai A 《Chemical communications (Cambridge, England)》2007,(23):2405-2407
Arynes were found to insert into carbon-halogen sigma-bonds of various acid halides, enabling acyl and halogen moieties to be introduced simultaneously into adjacent positions of aromatic rings. 相似文献
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Toshiyuki Iida Joji Ohshita Taisuke Uemura Hiroshi Fukuoka Nobuaki Ohta Kenji Komaguchi Yoshiteru Itagaki Masaru Shiotani Shoji Yamanaka Atsutaka Kunai 《Silicon Chemistry》2002,1(5-6):383-389
The spin states of a series of silicon- and carbon-bridged phenyl nitroxides were examined with respect to the temperature dependent ESR and SQUID measurements. Of those, a linear relationship between the ESR signal intensity and 1/T (T = absolute temperature) and an increase of χmolT along lowering T were observed for a compound having disilanylene-bridged m- and p-phenyl nitroxide units (Si2mp), indicating ferromagnetic spin-spin interaction in this molecule. In contrast to this, no clear intramolecular spin-spin interaction took place in the monosilanylene analogue (Si1mp). Mono- and disilanylene-bridged phenylnitroxides with p-, p- or m-, m-substitution (Si1pp,Si1mm, Si1pp, and Si2mm) exhibited the singlet ground state. The trisilanylene and siloxanylene bridges did not play an obvious role in the spin interaction, in either a ferro- or antiferromagnetic fashion, regardless of the substitution modes of the phenylenes. MO calculations on the model compounds provided a mechanistic interpretation for the high-spin interaction through the σ-π system. 相似文献
8.
Yoshida H Fukushima H Ohshita J Kunai A 《Journal of the American Chemical Society》2006,128(34):11040-11041
A zwitterion, generated from an aryne and an imine, has been demonstrated to serve as an excellent molecular scaffold for capturing CO2, which results in the straightforward formation of diverse benzoxazinones. 相似文献
9.
Togawa Y Harada K Akashi T Kasai H Matsuda T Nori F Maeda A Tonomura A 《Physical review letters》2005,95(8):087002
Using Lorentz microscopy to directly image vortices, we investigate vortex motion control and rectification in a niobium superconductor. We directly observe a net motion of vortices along microfabricated channels with a spatially asymmetric potential, even though the vortices were driven by an oscillatory field. By observing the individual motion of vortices, we clarify elementary processes involved in this rectification. To further demonstrate the ability to control the motion of vortices, we created a tiny vortex "racetrack" to monitor the motion of vortices in a closed circuit channel. 相似文献
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