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991.
Shigeru Kubota Toshimoto Moriwaki Torahiko Ando Akira Fukami 《Journal of polymer science. Part A, Polymer chemistry》1987,25(8):2241-2250
Polyquinazolones containing m-substituted phenyl groups (Br, Cl, F, CH3O, NO2, and CH3) on the quinazolone ring were synthesized in m-cresol, and their thermal properties were studied by using dynamic thermogravimetry and isothermal weight loss. Polyquinazolones with intrinsic viscosities in the range 0.2–1.6 dL/g were synthesized. The introduction of substituted groups into the pendant phenyl group resulted in a decrease in the glass transition temperature and the thermal stability. Oxidative thermal stability of the polyquinazolones was dependent on the position of substituted groups on the pendant phenyl group. The introduction of substituted groups into the meta position reduced thermal stability more than did the introduction into the para position. 相似文献
992.
Choji Kashima Akira Katoh Yuko Yokota Yoshimari Omote 《Journal of heterocyclic chemistry》1981,18(7):1469-1470
1,4,6-Trisubstituted 3,6-dihydro-2-(1H)pyrimidinones (Ia-d) easily underwent the ring opening reaction with hydroxylamine hydrochloride to afford the oximes (IIa-d) in good yields. In the case of 3,6-dihydro-6-methyl-I-phenyl-2-(1H)pyrimidinone (Ie), 2-anilinobutyronitrile (III) was obtained in addition to the oxime (IIe). Dihydro-2-(1H)pyrimidinone (IV) and -thiones (V and VI) did not undergo the ring opening reaction. 相似文献
993.
Xin -Tong Zhang Taketo Taguchi Hai -Bin Wang Qing -Bo Meng Osamu Sato Akira Fujishima 《Research on Chemical Intermediates》2007,33(1-2):5-11
The stability of the TiO2/ruthenium dye/CuI solid-state solar cell was investigated under continuous simulated sunlight illumination. The cells showed fast degradation under full-spectrum sunlight illumination, but showed rather good stability when the ultraviolet part of the illumination was removed. XPS measurements showed evidence that TiO2 could oxidize CuI in the presence of UV light. The photo-degradation mechanism of the cells is thus discussed on the basis of the photo-oxidative function of TiO2. The long-term stability of the solid-state dye-sensitized solar cell (DSSC) was found to be improved under simulated sunlight by coating the TiO2 porous electrode with an ultra-thin MgO layer, which was able to block the photo-oxidative activity of the TiO2. 相似文献
994.
Masafumi Hirano Kohtaro Osakada Hiroyuki Nohira Akira Miyashita 《The Journal of organic chemistry》2002,67(2):533-540
Full elucidation for stable, colorless, and meta-stable colored structures of a new spirobenzothiopyran has been achieved both in the solid state and in a solution. 1',3',3'-Trimethyl-6-nitrospiro[(2H)-1-benzothiopyran-2,2'-indoline] with an ester group as a substituent at the 8-position of 1-sp shows photochromism. The blue-green colored species resulted from UV irradiation (365 nm) in one minute and spontaneously bleaches within one minute in acetone and methanol at 27 degrees C. UV exposure (365 nm) of 1-sp in methanol for 3 h at room temperature results in the growth of deep blue needlelike single crystals of the open form of spirobenzothiopyran, photomerocyanine 1-pmc, whose structures in the solid state and in solution were obtained unambiguously. The X-ray structural analysis of 1-pmc revealed the molecular structure of the zwitterionic photomerocyanine with s-trans,s-trans conformation. 1-pmc is soluble to polar solvents and thermally returns to 1-sp. In the DMSO solution, 1-pmc is found to return slowly to 1-sp (1-pmc gave only 18% of 1-sp for 30 min at 22 degrees C). The detailed NMR studies in DMSO-d(6) including COSY and NOE techniques as well as isotope labeling of the compound showed the structure with s-trans,s-cis conformation in a solution. 相似文献
995.
Yoshiharu Tsujita Ryoko Ojika Koji Tsuzuki Akira Takizawa Takatoshi Kinoshita 《Journal of polymer science. Part A, Polymer chemistry》1987,25(4):1041-1048
Copoly(γ-stearly-L -glutamate-γ-methyl-L -glutamate)s with various compositions were synthesized by the ester exchange reaction of poly(γ-methyl-L -glutamate). Circular dichroism studies were carried out for solution and solid film as a function of the degree of stearylation and temperature. The slight and gradual temperature dependence of molecular ellipticity was observed for solution of all the copolyglutamates studied here and for the solid film of the copolyglutamate with the degree of stearylation of 16%, indicative of no reversal in the helix sense. However the remarkable change in negative molecular ellipticity with temperature was detected for the solid film of the copolyglutamate with a low degree of stearylation, e.g., 52%, whereas the drastic change in molecular ellipticity from a negative to positive value appeared for that with a higher degree of stearylation. This is discussed in terms of the reversal in the helix sense from a right- to left-handed α helix with the increase of temperature occurring at the melting temperature of the ordered side chain region. 相似文献
996.
Akira Kitani Masanori Kaya Syo-Ichi Tsujioka Kazuo Sasaki 《Journal of polymer science. Part A, Polymer chemistry》1988,26(6):1531-1539
Flexible polyaniline having excellent mechanical properties (e.g., elongation at break = 41% and tensile strength = 1.8 kg cm?2) was prepared by electrochemical reduction of ordinary polyaniline in organic solvents. The flexibility is directly related with the polymer morphology which was definitely affected by the nature of electrolyte anion. Perchlorate or tetrafluoroborate anion were found suitable to obtain flexible polyaniline. At the same time, it is essential that the polymer so prepared should be reduced (undoped) in some suitable organic solvents before making a flexible free standing film. 相似文献
997.
Rafael E. Vasquez Masaya Hono Akira Kitani Kazuo Sasaki 《Journal of Electroanalytical Chemistry》1985,196(2):397-415
The contribution of the heterogeneous (involving non-adsorbed solution species) and surface path (involving adsorbed species) to the electrode processes of aromatic nitro compounds has been studied as a function of the surface conditions of glassy carbon (GC-20) by linear sweep voltammetry (LSV) and cyclic voltammetry (CV). The influence of adsorption was negligible at the freshly polished electrodes. Oxidative electrochemical pretreatment led to the formation of active sites at which the adsorption of the reactant resulted in enhanced electron-transfer rates. The nature of the adsorption process and the characteristics of the electrode reaction in the adsorbed state were studied in detail for p-nitrotoluene. The adsorption followed the Frumkin isotherm with an interaction parameter of 1.2, indicating moderate attractive interactions between the adsorbed molecules. The rate constant for the adsorbed species was of the order of 105, higher than the apparent heterogeneous rate constant of p-nitrotoluene in the solution phase. The magnitude of the potential shift and the strength of adsorption varied with the relative position and electron-withdrawing power of the substituent in the aromatic ring of nitrobenzene. Free radical coupling was selectively catalysed at electrochemically pretreated electrodes. 相似文献
998.
Nerol is cyclized to terpinyl chloride or bromide in the presence of TiX4-PhNHMe (1:1) complex in dichloromethane at ?23 °C, while cyclization of ()-allylic alcohols CH2=CR-CH2CH2CMe=CHCH2OH (R = H, Me, Cl) produces seven-membered ring products in fair yields. 相似文献
999.
Me2AlSPh or Me2AlSeMe adds to α,β-unsaturated carbonyl compounds in 1,4-fashion. The resulting aluminium enolates react with aldehydes effectively to afford the adducts of the title anion after formal PhSH (or MeSeH)-elimination. 相似文献
1000.
William R. Dolbier Jr. Samia Aït-Mohand Tatiana A. Sergeeva Akira Mitani Rolf W. Winter 《Journal of fluorine chemistry》2006,127(10):1302-1310
Both SF5Cl and SF5Br undergo smooth, high yield addition to alkenes and alkynes under the mild free radical chain reaction conditions of triethylborane initiation at low temperature, although the SF5Br chemistry is somewhat limited by its competing high electrophilic reactivity with electron rich alkenes. The SF5Cl addition reaction is relatively insensitive to a wide variety of non-allylic functionalities. 相似文献