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21.
Suguru Motokucho Atsushi Sudo Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2007,45(19):4459-4464
A five‐membered cyclic dithiocarbonate having phenylcarbamate moiety 1 underwent cationic ring‐opening polymerization by using methyl trifluoromethanesulfonate as an initiator in nitrobenzene at 60 °C. Both of the corresponding first‐order kinetic plot and conversion‐molecular weight plot showed linearity to suggest the living fashion of the polymerization, which was then supported by two‐stage polymerization experiment. The living fashion as well as the regioselective formation of the repeating unit suggested significant contribution of the neighboring group participation of the carbamate group to form a stabilized cationic propagating end, of which structure was confirmed by performing an equimolar reaction of 1 and methyl trifluoromethanesulfonate with analyzing the resulting species by NMR spectroscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4459–4464, 2007 相似文献
22.
Yu Matsuda Hideo Mori Yoshiki Sakazaki Toru Uchida Suguru Suzuki Hiroki Yamaguchi Tomohide Niimi 《Experiments in fluids》2009,47(6):1025-1032
Pressure-sensitive paint (PSP) has the potential as a diagnostic tool for pressure measurement in high Knudsen number regime
because it works as a so-called “molecular sensor”. However, there are few reports concerning application of PSP to micro-devices,
because conventional PSPs are too thick owing to polymer binders. In our previous work, we adopted the Langmuir–Blodgett (LB)
technique to fabricate the pressure-sensitive molecular film (PSMF) using Pd(II) Mesoporphyrin IX (PdMP), which has pressure
sensitivity only in the low pressure range (below 130 Pa). In this study, aiming for pressure measurement under an atmospheric
pressure condition, we have constructed four samples of PSMFs composed of Pt(II) Mesoporphyrin IX (PtMP), Pt(II) Mesoporphyrin
IX dimethylester (PtMPDME), Pt(II) Protoporphyrin IX (PtPP) and Cu(II) Mesoporphyrin IX dimethylester (CuMPDME) as luminescent
molecules. The pressure sensitivity of those PSMFs was measured, and it was clarified that the pressure sensitivity of PSMF-PtMP
is the highest among the four samples. Moreover, the temperature dependency of PSMF-PtMP was investigated, and we found that
the temperature dependency of PSMF is dominated not by the oxygen diffusion in the layer, but by non-radiative deactivation
process of excited luminescent molecules. 相似文献
23.
Suguru Motokucho Atsushi Sudo Fumio Sanda Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2004,42(10):2506-2511
A novel branched polycarbonate with a hydroxyl group at the chain end was synthesized by the copolymerization of glycidol with carbon dioxide (CO2). The copolymerization was carried out with 5 mol % of an alkali metal halide or quaternary ammonium salt as a catalyst under atmospheric CO2. The obtained poly(glycidol‐co‐carbon dioxide) was O‐benzoylated and O‐silylated, and the corresponding polymers were analyzed with IR, size exclusion chromatography, 13C NMR, and 29Si NMR. The IR spectroscopy analysis of the O‐benzoylated polymer revealed that the maximum incorporation degree of the carbonate group was 90% (i.e., the CO2/glycidol composition ratio was 0.9:1.0). The incorporation of CO2 as a carbonate unit was also confirmed by the treatment of this polymer with n‐butylamine, which caused the aminolysis of the carbonate and led to degraded products. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2506–2511, 2004 相似文献
24.
Hiroyoshi Kamogawa Toshiaki Masui Suguru Amemiya 《Journal of polymer science. Part A, Polymer chemistry》1984,22(2):383-390
Reversible photocolor developments of viologens embedded in poly(N-vinyl-2-pyrrolidone) films, a typical polar aprotic solid matrix, were found to be affected by the kinds of viologen cation as well as the paired anion. The color developments in the corresponding low-molecular-weight solvents are connected closely to the solubility of viologens in these solvents; viologens are highly sensitive in the polar aprotic solvents in which they have poor solubilities, such as N-methyl-2-pyrrolidone and hexamethyl phosphoric triamide. These facts confirm the color-development mechanism consistings of electron transfer to the photoexcited viologen cation from the paired anion in polar aprotic solid matrices such as poly(N-vinyl-2-pyrrolidone). 相似文献
25.
Suguru Nagae Yasuo Suda Yoshiaki Inaki Kiichi Takemoto 《Journal of polymer science. Part A, Polymer chemistry》1989,27(8):2593-2609
Poly-L -lysine (PLL) derivatives containing pendant nucleic acid base, such as thymine or adenine, were bonded successfully to 3-aminopropylsilanized silica (APS-silica) and silica gel. These resins were found to be useful as the column of high performance liquid chromatography (HPLC) for the selective separation of oligoethyleneimine derivatives having pendant thymine or adenine bases. 相似文献
26.
Hideaki Takahashi Fumihiro Miki Hajime Ohno Ryohei Kishi Suguru Ohta Shin-ichi Furukawa Masayoshi Nakano 《Journal of mathematical chemistry》2009,46(3):781-794
The reaction mechanism for the dehydration of 1,4-butanediol in hot water has been investigated by means of the hybrid quantum
mechanical/molecular mechanical approach combined with the theory of energy representation (QM/MM-ER). We have assumed that
the proton transfers along the hydrogen bonds of the water molecules catalyze the reaction, where the transition state (TS)
forms a singlet biradical electronic structure. It has been revealed by the simulation that the biradical electronic state
at the TS changes to zwitterionic structure in solution due to the hydration of the polar solvent. Such the electronic structure
change gives rise to the substantial stabilization of the TS in hot water. As a result, the water-catalytic path becomes more
favorable in aqueous solution than another possible path that proceeds without proton transfers as opposed to the reaction
mechanism in the gas phase. Furthermore, the activation free energy computed by the present method is in excellent agreement
with the experimental result. 相似文献
27.
Ogoshi T Kanai S Fujinami S Yamagishi TA Nakamoto Y 《Journal of the American Chemical Society》2008,130(15):5022-5023
Condensation of 1,4-dimethoxybenzene (DMB) with paraformaldehyde in the presence of BF3.O(C2H5)2 gave novel para-bridged pentacyclic pillar DMB (DMpillar[5]arene). Moreover, para-bridged pentacyclic hydroquinone (pillar[5]arene) was prepared. Pillar[5]arene formed 1:1 host-guest complexes with dialkyl viologen and alkyl pyridinium derivatives. However, pillar[5]arene did not form complexes with the diadamantyl viologen derivative since a bulky adamantyl group was unable to thread the cavity of pillar[5]arene. 相似文献
28.
Xiumei Chen Suguru Jinguu Suzuka Nishimura Yasunao Oyama Kazutaka Terashima 《Journal of Crystal Growth》2002,240(3-4):445-453
The density and the surface tension of molten calcium fluoride have been measured in the temperature range from 1690 to 1790 K by an improved Archimedian method and a ring depressing technique (J. Crystal Growth 187 (1998) 391), respectively. The ring depressing technique was demonstrated as an effective technique to measure the surface tension in comparison with the conventional ring pulling technique. The density varied with the temperature change corresponding to a linear relationship: ρ=3.767−6.94×10−4T (K). The density of the CaF2 melt at the melting point is 2.594 g/cm3, which is equal to the result obtained by Shiraishi and Watanabe (Bull. Res. Inst. Miner. Dressing Metal, Tohoku Univ. 34 (1978) 1), but the temperature coefficient of the density is different from the results obtained by other investigators. The thermal expansion coefficient of calcium fluoride melt linearly increases with temperature heating. The surface tension of molten calcium fluoride indicates a negative linear relationship as a function of the melt temperature: γ(T)=442.4−0.0816×T(K) (mN/m). The surface tension measured using the ring depressing technique is larger than those results obtained by other techniques. 相似文献
29.
Suguru Ito 《Tetrahedron letters》2010,51(32):4243-5830
In the presence of a catalytic amount of mesoporous aluminosilicate (Al-MCM-41), both allyltrimethylsilane and silyl enol ether reacted with various acetals under mild reaction conditions to afford the corresponding homoallyl ethers and β-alkoxy ketones, respectively. The catalyst was easily recovered from the reaction mixture and could be reused in the same reaction without a significant loss of catalytic activity. Moreover, Al-MCM-41 exhibited high chemoselectivity for acetal over aldehyde in the reactions. 相似文献
30.
Youngchan Kim Dr. Kazuya Kanemoto Ken Shimomori Prof. Dr. Takamitsu Hosoya Prof. Dr. Suguru Yoshida 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(28):6136-6140
Catalytic thiolation and azidation of a single C−F bond of trifluoromethylarenes were achieved assisted by an ortho-silyl group with all-in-one reagents to generate a trityl cation and nucleophiles. The reactions catalyzed by ytterbium triflate efficiently afforded a wide variety of difluoromethylenes avoiding the further C−F bond cleavage, by virtue of the mild conditions without the generation of a Brønsted acid. 相似文献