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611.
Mio Matsumura Aya Tanatani Tomoyo Kaneko Isao Azumaya Hyuma Masu Daisuke Hashizume Hiroyuki Kagechika Atsuya Muranaka Masanobu Uchiyama 《Tetrahedron》2013
We synthesized porphyrinylamide 4b and its N-methylated derivative 5b. Direct N-methylation of porphyrinylamides 4 proved unsuccessful, so 5b was obtained via N-methylation of 5-aminoporphyrin 10 with potassium hexamethyldisilazide. The secondary amide 4b exists in trans-amide form, while N-methylated amide 5b exists in the cis-amide form, both in solution and in the crystal. Thus, N-methylation of the amide bond of 4b resulted in trans to cis conformational alteration. 相似文献
612.
Yuanyuan Liu Wenmu Li Antisar R. Hlil Sumiko Matsumura Yuezhong Meng Allan S. Hay 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8):784-787
3-(4-Fluorobenzoyl)carbazole was synthesized by a Friedel-Crafts reaction of carbazole with 4-fluorobenzoylchloride. 1H-NMR and MALDI-TOF MS confirmed the structure and the purity. Copolymers of these NH/OH-containing monomers were prepared with 4, 4′-biphenol and bis(4-fluorophenyl)sulfone as comonomers by combined C-O and C-N coupling reactions with activated difluorides. These copolymers were soluble in N-methylpyrrolidinone (NMP), dimethylsulfoxide (DMSO), N,N-dimethylacetamide (DMAc) and dimethylformamide (DMF). The inherent viscosities of the copolymers in NMP solutions at 30°C were all around 0.8 dL/g. They could be easily cast into tough films from NMP solutions. The copolymers exhibited Tgs ranging from 238°C to 282°C. Thermal stabilities by TGA showed no weight loss below 400°C and the temperatures of 5% weight loss ranged from 535°C to 558°C. The homopolymer of 3-(4-fluorobenzoyl)carbazole was insoluble in common solvents and had a Tg of 332°C, and temperature of 5% weight loss of 560°C. UV-VIS absorption and fluorescence of the polymers are also presented. 相似文献
613.
H. Hatakeyama H. Matsumura T. Hatakeyama 《Journal of Thermal Analysis and Calorimetry》2013,111(2):1545-1552
Rigid polyurethane (PU) foams having saccharide and castor oil structures in the molecular chain were prepared by reaction between reactive alcoholic hydroxyl group and isocyanate. The apparent density of PU foams was in a range from 0.05 to 0.15 g cm?3. Thermal properties of the above polyurethane foams were studied by differential scanning calorimetry, thermogravimetry and thermal conductivity measurement. Glass transitions were observed in two steps. The low-temperature side glass transition was observed at around 220 K, regardless of castor oil content. This transition is attributed to the molecular motion of alkyl chain groups of castor oil. The high-temperature side glass transition observed in the temperature range from 350 to 390 K depends on the amount of molasses polyol content. The high-temperature side glass transition is attributed to the molecular motion of saccharides, such as sucrose, glucose, fructose as well as isocyanate phenyl rings, which act as rigid components. Thermal decomposition was observed in two steps at 570 and 620–670 K. Thermal conductivity was observed at around 0.032 J sec?1 m?1 K?1. Compression strength and modulus of PU foams were obtained by mechanical test. It was confirmed that the thermal and mechanical properties of PU foams could be controlled by changing the mixing ratio of castor oil and molasses for suitable practical applications. 相似文献
614.
Arata Yajima Saki KounoTohru Dairi Manami MogiRyo Katsuta Haruo SetoTomoo Nukada 《Tetrahedron letters》2011,52(38):4934-4937
The first synthesis of (±)-cyclic dehypoxanthine futalosine (cyclic DHFL), a biosynthetic intermediate in the futalosine pathway for menaquinones operating in microorganisms, has been achieved. Efficient growth of the Streptomyces coelicolor mutant, which lacks the cyclic DHFL synthetase gene (mqnC gene) was observed in the presence of synthetic (±)-cyclic DHFL. 相似文献
615.
Houjou H Takezawa S Oyamada I Matsumura K Seino H Yoshikawa I Mizobe Y Araki K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(4):1122-1127
We have developed a novel triphenylmethane-based hexanuclear zinc complex that exhibits peculiar photochemical and photophysical properties. Upon UV irradiation, the compound turned from colorless to reddish purple, while the color of emission turned from blue to red. The color change was attributed to an oxidation of the ligand part. It was suggested that an intramolecular energy-transfer mechanism operates to give rise to the red emission. The UV treatment of a single crystal results in simultaneous emission of orthogonally polarized blue and red light. This color switching, namely linear dichroic emission was so distinct that one can recognize with by sight through optical microscope. The columnar arrangement of molecules in the crystal clearly accounts for the observed polarization of the emission. 相似文献
616.
Jarrige I Rueff JP Shieh SR Taguchi M Ohishi Y Matsumura T Wang CP Ishii H Hiraoka N Cai YQ 《Physical review letters》2008,101(12):127401
The pressure-induced valence transition in TmTe was investigated by resonant inelastic x-ray scattering at the Tm L3 edge, a powerful probe of the rare-earth valent state. The data are analyzed within the Anderson impurity model which yields key parameters such as the Tm 4f-5d hybridization. In addition to the general tendency of the f electrons towards delocalization, we find a plateau in both the Tm valence and hybridization pressure dependences between 4.3 and 6.5 GPa which is interpreted in terms of an n-channel Kondo (NCK) screening process. This behavior is at odds with the usually continuous, single-channel Kondo-like f delocalization while being supported by the seminal calculations of the NCK temperature in Tm ion by Saso et al. Our study raises the interesting possibility that an NCK effect realized in a compressed mixed-valent f system could impede the concomitant electron delocalization. 相似文献
617.
Shuichi Matsumura Satoshi Harai Kazunobu Toshima 《Macromolecular rapid communications》2001,22(3):215-218
The enzymatic degradation and polymerization using an enzyme were carried out with respect to the establishment of a sustainable chemical recycling system for poly(trimethylene carbonate) [P(TMC)] which is a potentially biodegradable synthetic plastic. The enzymatic transformation of P(TMC)s having an Mn of 3000~48000 using Candida antarctica lipase (lipase CA) in acetonitrile at 70 °C afforded the corresponding cyclic monomer, trimethylene carbonate (TMC: 1,3‐dioxan‐2‐one), in a yield of up to 80%. Thus obtained TMC readily polymerized again using both fresh lipase CA and recovered lipase CA. 相似文献
618.
Shuichi Matsumura Hiroki Ebata Reiko Kondo Kazunobu Toshima 《Macromolecular rapid communications》2001,22(16):1325-1329
The enzymatic transformation of poly(ϵ‐caprolactone) (PCL) into repolymerizable oligomers in supercritical carbon dioxide (scCO2) using an enzyme was carried out in order to establish a sustainable chemical recycling system for PCL, which is a typical biodegradable synthetic plastic. The enzymatic conversion of PCL beads having an M̄n of 110 000 using Candida antarctica lipase (lipase CA) in scCO2 containing small amounts of water quantitatively afforded CL oligomers at 40°C. The CL oligomers were readily repolymerized using the same enzyme to produce high‐molecular weight PCL. 相似文献
619.