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101.
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103.
Yuki Goto Masahiro Shiosaki Takeshi Hanamoto Masato Yoshida Hideo Sawada 《Colloid and polymer science》2013,291(5):1211-1217
Fluoro(silyl)acetylenes, which were prepared by reaction of 1,1-difluoroethylene with silyl chlorides, reacted with triethylamine to give dark-brown colored polyfluoro(silyl)acetylene powders in excellent to moderate isolated yields. In contrast, the corresponding nonfluorinated acetylene was unable to react with triethylamine at all to afford poly(silyl)acetylene under similar conditions. Polyfluoro(silyl)acetylenes thus obtained were nanometer size-controlled cubic fine particles with a good dispersibility and stability in a variety of solvents. These polyfluoro(silyl)acetylene nanoparticles exhibited clear absorption and emission spectra related to the conjugated units in polymer main chain. Furthermore, these polyfluoro(silyl)acetylene nanoparticles were applied to the surface modification of poly(methyl methacrylate) [PMMA] film to exhibit a higher oleophobicity imparted by fluorine on their surface, compared to that on the reverse side. Figure
New polyfluoro(silyl)acetylenes were prepared by reaction of the creesponding fluoro(silyl)acetylenes with triethylamine in excellent to moderate isolated yields. In contrast, the corresponding nonfluorinated silylacetylene was unable to give poly(silyl)acetylene under similar conditions. These polyfluoro(silyl)acetylenes thus obtained can form the nanometer size-controlled cubic fine particles (within 100 nm) in a variety of solvents. 相似文献
104.
Hideaki Murasugi Dr. Shohei Kumagai Dr. Hiroaki Iguchi Prof. Dr. Masahiro Yamashita Dr. Shinya Takaishi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9885-9891
Crystal structures of a series of organic–inorganic hybrid gold iodide perovskites, formulated as A2[AuII2][AuIIII4] [A=methylammonium (MA) ( 1 ) and formamidinium (FA) ( 2 )], A′2[I3]1−x[AuII2]x[AuIIII4] [A′=imidazolium (IMD) ( 3 ), guanidinium (GUA) ( 4 ), dimethylammonium (DMA) ( 5 ), pyridinium (PY) ( 6 ), and piperizinium (PIP) ( 7 )], systematically changed depending on the cation size. In addition, triiodide (I3−) ions were partly incorporated into the AuI2− sites of 3 – 7 , whereas they were not incorporated into those of 1 and 2 . Such a difference comes from the size of the organic cation. Optical absorption spectra showed characteristic intervalence charge-transfer bands from AuI to AuIII species, and the optical band gap increased as the size of the cation became larger. 相似文献
105.
Zhao‐Yang Li Jing‐Wei Dai Marko Damjanovi Takuya Shiga Jin‐Hua Wang Jia Zhao Hiroki Oshio Masahiro Yamashita Xian‐He Bu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(13):4383-4388
We report three self‐assembled iron complexes that comprised an anti‐parallel open form (o‐ L anti), a parallel open form (o‐ L syn), and a closed form (c‐ L ) of diarylethene conformers. Under kinetic control, FeII2(o‐ L anti)3 was isolated, which exhibited a dinuclear structure with diamagnetic properties. Under light‐irradiation control, FeII2(c‐ L )3 was prepared and exhibited paramagnetism and spin‐crossover behaviour. Under thermodynamic control and in the presence of indispensable [FeIII(Tp*)(CN)3]?, FeII2(o‐ L anti)3 and FeII2(c‐ L )3 transformed into tetranuclear FeIII2FeII2(o‐ L syn)2, which exhibited complete spin‐crossover behaviour at T1/2=353 K. 相似文献
106.
Jun Kikuchi Masahiro Terada 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(25):8546-8550
An enantioselective intermolecular addition reaction of azlactones, as carbon nucleophiles, with styrene derivatives, as simple olefins, was demonstrated using a newly developed chiral Brønsted acid catalyst, namely, F10BINOL‐derived N‐triflyl phosphoramide. Addition products having vicinal tetrasubstituted carbon centers, one of which is an all‐carbon quaternary stereogenic center, were formed in good yields with moderate to high stereoselectivities. Extremely high acidity of the new chiral Brønsted acid was confirmed by its calculated pKa value based on DFT studies and is the key to accomplishing not only high catalytic activity but also efficient stereocontrol in the intermolecular addition. 相似文献
107.
A mechanistic study was carried out for the asymmetric Michael addition reaction of malonates to enones catalyzed by a primary amino acid lithium salt to elucidate the origin of the asymmetric induction. A primary β-amino acid salt catalyst, O-TBDPS β-homoserine lithium salt, exhibited much higher enantioselectivity than that achieved with the corresponding catalysts derived from α- and γ-amino acids for this reaction. Detailed studies of the transition states with DFT calculations revealed that the lithium cation and carboxylate group of the β-amino acid salt catalyst have important roles in achieving high enantioselectivity in the Michael addition reaction of malonates to enones. 相似文献
108.
Kiyoharu Tadanaga Koji Morita Keisuke Mori Masahiro Tatsumisago 《Journal of Sol-Gel Science and Technology》2013,68(2):341-345
Silica nanoparticles with high concentration were prepared by the sol–gel process based on the Stöber method using tetraethoxysilane as a starting material. It was found that silica sol with about 4 wt% in concentration and with a diameter of about 10 nm was obtained by controlling the reaction conditions in the Stöber process. By removing the solvent under a reduced pressure, the particle concentration was increased up to 15 wt% without aggregation. 相似文献
109.
Kazumasa Inoue Masahiro Hosoda Shinji Tokonami Tetsuo Ishikawa Masahiro Fukushi 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(3):2009-2015
The temporal variation of the radon concentration, and the radon and thoron concentrations every 3 months for a year were measured using two types of devices in a landmark skyscraper, the Tokyo Metropolitan Government Daiichi Building. In the measurement of temporal variation of the radon concentration using a pulse type ionization chamber, the average radon concentration was 21 ± 13 Bq m?3 (2–68 Bq m?3). The measured indoor radon concentration had a strong relationship with the operation of the mechanical ventilation system and the activities of the office workers. The radon concentration also increased together with temperature. Other environmental parameters, such as air pressure and relative humidity, were not related to the radon concentration. In the long-term measurements using a passive radon and thoron discriminative monitor, no seasonal variation was observed. The annual average concentrations of radon and thoron were 16 ± 8 and 16 ± 7 Bq m?3, respectively. There was also no relationship between the two concentrations. The annual average effective dose for office workers in this skyscraper was estimated to be 0.08 mSv y?1 for 2000 working hours per year. When considering the indoor radon exposure received from their residential dwellings using the annual mean radon concentration indoors in Japan (15.5 Bq m?3), the annual average effective dose was estimated to be 0.37 mSv y?1. This value was 31 % of the worldwide average annual effective dose. 相似文献
110.
Yoshimi Kurimura Masahiro Saito Kyota Hiramatsu Yoshihiro Sairenchi 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(9-11):1275-1292
Electron transfer reactions of Co(NH3)5PAA (PAA = polyacrylic acid) with either the polyanionic polymer-bound ferrous chelate, Fe11P-SS (P-SS = vinylbenzylaminediacetate-co-styrenesulfonate) or the uncharged polymer-bound ferrous chelate, Fe11P-VPRo (P-VPRo = vinylbenzylaminediacetate-co-vinylpyrrolidone), and the Ru(bpy)2+ 3 photosensitized reduction of Co(NH3)5PAA have been investigated in aqueous solutions at pH 5.4, I = 0.06 (I is ionic strength), and 25°C. For the ferrous chelate reductions, the second-order rate constants for Fe11-PSS and Fe11P-VPRo were almost equal to that for the corresponding nonpolymer-bound ferrous chelate, Fe11BDA (BDA = benzylaminediacetate). The results indicate that there is no appreciable steric hindrance due to the polymer chains of the polymer-bound ferrous chelates and that the effect of columbic repulsion force between the polyanion chains can be ignored for the reaction of Co(NH3)5PAA with Fe11P-SS. The results also suggest that there are two kinds of the pendant Co(III) species, “reactive” and “inert.” The inert Co(III) species are shielded by the polymer chains from attack of the Fe(II) chelates that are present in the bulk solutions. A similar reaction behavior was observed in the Ru(bpy)2+ 3 photosensitized reduction of Co(NH3)5PAA at pH 5.4. For the Co(III) complex having an extremely few Co(III) complex moieties on the polymer chain, almost all of the Co(III) groups were hardly reduced by the excited state of Ru(bpy)2+ 3, and reverse quenching occurred due to binding of the Ru(bpy)2+ 3 to the polyacrylic acid chain of the polymer complex. On the other hand, for Co(NH3)5PAA with a relatively large number of the Co(III) moieties on the polymer chain, lifetime measurements at a higher concentration of the Ru(bpy)2+ 3 showed a double-exponential fit, which suggests that there are two parallel decay processes. The fast and slow components mainly correspond to the decays: Ru(bpy)2+ 3 quenched by Co(III) and reverse quenching due to binding of Ru(bpy)2+ 3 into the compact polymer chains. 相似文献