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51.
Kazunori Matsui Takayuki Kaneko Yasunori Yaginuma Masaru Ryu 《Journal of Sol-Gel Science and Technology》1997,9(3):273-277
A spin probe TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxy) was dissolved in a tetraethyl orthosilicate sol-gel reaction
system and measured by electron spin resonance spectroscopy at 295 K. The nitrogen hyperfine coupling constant was from 1.64–1.66
mT in the sol-gel solutions. The values were sensitive to the ethanol-to-water ratio of the solutions. The hyperfine coupling
constant in the xerogels was 1.70 mT, which was almost the same as that in water, indicating that the probe molecules were
trapped in silica pores with water adsorbed on the silica surfaces. The motion of TEMPOL in the xerogels was considerably
slower than in the sol-gel solutions. The local viscosity estimated was from 70–90 cP. The ESR spectra of TEMPOL were altered
during the sol-gel process, indicating that adsorbed water on the silicas surfaces has an important role for trapping organic
molecules in sol-gel glasses. 相似文献
52.
Lin Wang Shinji Takeoka Eishun Tsuchida Satoru Tokuyama Takahiro Mashiko Tadashi Satoh 《先进技术聚合物》1992,3(1):17-21
The carbonyl hemoglobin (CO-Hb), which was used to prevent denaturation (metHb) during the preparation of samples, was encapsulated into lipid vesicles constituted from unsaturated phospholipid, cholesterol and unsaturated fatty acid. Unsaturated components were polymerized by γ-irradiation to enhance the stability of bilayer membrane. An aqueous dispersion of resulting Hb vesicles was freeze-dried in the presence of saccharides (50–200 mM) to obtain a dehydrated powder of Hb vesicles. Change in the vesicle size, the leakage of encapsulated Hb and the oxidation of Hb to metHb were not observed. Therefore, the long-term storage of Hb vesicles can be realized as a dry powder. 相似文献
53.
Nishii Y Wakasugi K Koga K Tanabe Y 《Journal of the American Chemical Society》2004,126(17):5358-5359
Chirality exchange benzannulation of optically active (1S)-aryl(aryl')-2,2-dichlorocyclopropylmethanols (>99% ee) using TiCl4 successfully proceeded to give axially chiral (M)-alpha-arylnaphthalenes with excellent levels of stereo induction (>99% ee). This unique transformation involves the single-step chirality exchange from sp3 central chirality to axial chirality, that is, a type of excellent memory effect. 相似文献
54.
Hiroyuki Nishide Kenichi Shinohara Eishun Tsuchida 《Journal of polymer science. Part A, Polymer chemistry》1981,19(5):1109-1117
Iron(III) proto-porphyrin IX dimethyl ester (HDME) can copolymerize with π-conjugated monomers binding at one end of the polymer chain. Apparent Q, e values of HDME were Q = 70 and e = ?0.17. The copolymerization of HDME with π-unconjugated monomer was feasible by using π-conjugated monomer as a third component. When unconjugated vinylimidazoles were used as monomers, the obtained ternary copolymers of HDME formed intramacromolecular complexes of iron(II) porphyrin with vinylimidazole residues, which gave stable carbon monoxide adducts. 相似文献
55.
Tadao Ishii Takeshi Tsuchida Ryusaburo Furuichi Hiroshi Haga Kazuhiko Kudo 《Thermochimica Acta》1982,53(1):89-103
The chlorination processes of fly ash and bauxite in the presence of carbon were studied by means of a gas-flow type DTA, X-ray analysis and SEM observation, and the reactivity of Al-compounds as their constituents was compared. In the case of fly ash, the exothermic peak due to the formation of AlCl3 (mainly) and FeCl3 appeared at about 790–920°C. The reactivity of Al estimated from the DTA peak temperature depended on the particle size, carbon content and preparation temperature of fly ash, and was much lower than that of bauxite. Fractional conversion of Al was about 60–70%, when fly ash (?300 mesh) was heated up to 900°C in Cl2 at 5°C min?1 of heating rate. In the case of bauxite, two exothermic peaks due to the chlorination of Fe and Al appeared at about 270 and 490°C, respectively. The chlorination of Al was completed at 550°C under the above conditions. 相似文献
56.
Radical polymerization of metal-coordinated monomers with ligands of pyrrole-containing schiff bases
Eishun Tsuchida Tsugikazu Tomono Kenji Honda 《Journal of polymer science. Part A, Polymer chemistry》1974,12(6):1243-1255
The copper complexes and the cobalt complex with the ligand of 3-(2-pyrrolylmethyl-enimino)propene-1 (PIP) or p-(2-pyrrolylmethylenimino)styrene (PIS) were synthesized and homopolymerizations and the copolymerization with styrene, acrylonitrile, methyl methacrylate and acrylic acid studied. In the polymerization of chelate monomers, inhibition of radical polymerization by the central metal ion was observed, but the chelate polymer could be obtained only if the initiator was present in higher concentrations in the feed. It is considered that the strength of inhibition depends on the electronic configuration of d-orbitals of the central metal ion. The initiation mechanism of the cupric chelate monomer may be reduction of the metal ion by the redox reaction with a primary radical via the intramolecular electron transfer through the π-conjugated system of the ligand prior to the propagation step. This mechanism was verified by studying the redox reaction of various copper complexes with DPPH. In the system of the copper complex containing PIS and acylic acid the alternating copolymer could be obtained at any mole fraction of monomer mixture in feed. 相似文献
57.
Yoshikuni Uchida Masao Yoshida Osamu Nishiara Kazunori Matsui 《Journal of Sol-Gel Science and Technology》2003,26(1-3):177-180
Silica gels doped with Cu2+ ions were prepared from the (3-aminopropyl) trimethoxysilane (APTMOS)/tetraethoxysilane (TEOS) systems. Sols showed a broad absorption peak at 640 nm, suggesting 3–5 coordination of the aminopropyl groups to Cu2+. For gels prepared from APTMOS and dried at room temperature, the 640 nm peak decreased and a red-shifted absorption appeared below 400 nm within a few months. The luminescence spectra of the xerogels showed emission bands at 430–470 and 510 nm. The former and latter bands are ascribed to Cu+ monomer and dimer emissions, respectively. These results indicate that Cu2+ ions are reduced to Cu+. When xerogels were prepared from APTMOS/TEOS = 1 (vol/vol), the color of xerogels was blue with an absorption peak at around 670 nm, indicating no reduction of Cu2+ ions. 相似文献
58.
59.
Photons propagating in strong magnetic fields are subject to a phenomenon called the “vacuum birefringence” where refractive indices of two physical modes both deviate from unity and are different from each other. We compute the vacuum polarization tensor of a photon in a static and homogeneous magnetic field by utilizing Schwinger’s proper-time method, and obtain a series representation as a result of double integrals analytically performed with respect to proper-time variables. The outcome is expressed in terms of an infinite sum of known functions which is plausibly interpreted as summation over all the Landau levels of fermions. Each contribution from infinitely many Landau levels yields a kinematical condition above which the contribution has an imaginary part. This indicates decay of a sufficiently energetic photon into a fermion–antifermion pair with corresponding Landau level indices. Since we do not resort to any approximation, our result is applicable to the calculation of refractive indices in the whole kinematical region of a photon momentum and in any magnitude of the external magnetic field. 相似文献
60.
Kyoichi Hanada Juntaro Nogami Prof. Dr. Kazunori Miyamoto Norihiko Hayase Dr. Yuki Nagashima Yusuke Tanaka Dr. Atsuya Muranaka Prof. Dr. Masanobu Uchiyama Prof. Dr. Ken Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(36):9313-9319
The enantioselective synthesis of aza[6] and [7]helicene-like molecules have been achieved by the cationic rhodium(I)/axially chiral biaryl bisphosphine complex-catalyzed intramolecular [2+2+2] cycloaddition of cyanodiynes. This protocol was successfully applied to the diastereo- and enantioselective synthesis of an S-shaped double aza[6]helicene-like molecule with a high ee value of 89 %. Although no epimerization and racemization were observed in the double carbo[6]helicene-like molecule at 80 °C, epimerization and racemization of the double aza[6]helicene-like molecule proceeded at 80 °C. This double aza[6]helicene-like molecule showed good fluorescent quantum yields and chiroptical responses under both neutral and acidic conditions. 相似文献