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141.
Koji Takagi Takato Isomura Yohei Ito Masanori Sakaida Shusaku Nagano Takahiro Seki 《Journal of polymer science. Part A, Polymer chemistry》2011,49(23):4993-5000
The Suzuki (for O1 – O3 ) and Stille (for O4 ) coupling polymerization of 2‐(phenylazo)imidazole bearing the benzyl protecting group at the 1‐position gave conjugated oligomers. The transformation from the neutral imidazole in the conjugated oligomer O2 , consisted of the alternating 2,5‐didecyl‐1,4‐phenylene unit, to the cationic imidazolium salt O2S was performed. Depending on the chemical structure of coupling partners, the absorption maximum of conjugated oligomers showed red shift or blue shift from that of the model compound M with the benzene ring at the 4,5‐positions. The absorption maximum wavelength of the cationic conjugated oligomer O2S showed a blue shift from that of the neutral conjugated oligomer O2 . The trans‐to‐cis photoisomerization of the azoimidazole unit in conjugated oligomers was observed by irradiating the light at 436 nm, and the conversion degree to the cis structure had a rough correlation with the maximum absorption wavelength of materials. The trans‐to‐cis photoisomerization in the film state was sluggish. On the other hand, the cis‐to‐trans thermal isomerization of the azoimidazole unit was confirmed and the absorbance returned to the initial state before the photoisomerization. The trans‐to‐cis photoisomerization of the cationic conjugated oligomer O2S required large energy, and the prolonged light irradiation might decompose the azoimidazole unit. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011. 相似文献
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145.
Yapeng Fang Saphwan Al-Assaf Glyn O. Phillips Katsuyoshi Nishinari Takahiro Funami Peter A. Williams 《Structural chemistry》2009,20(2):317-324
The physiological functions of the two ions, Ca2+ and H+, in controlling mechanical properties of plant cell wall are reviewed. The interactions of these ions with major cell wall
polysaccharides during cell growth and development are described. Experimental results for Ca2+/H+-induced molecular associations of some polysaccharides in solutions are also given. This article aims to bridge the understandings
of molecular associations in solutions (in vitro) with those occurring in cell wall matrix of high order structure (in vivo). 相似文献
146.
Takashi Yoshida Rong Lu Shuqin Han Kazuyuki Hattori Takahiro Katsuta Kei‐Ichi Takeda Kazutoshi Sugimoto Masamitsu Funaoka 《Journal of polymer science. Part A, Polymer chemistry》2009,47(3):824-832
For the synthesis of a new biologically functional polymer from a natural resource by an environment‐friendly method, the laccase‐catalyzed polymerization of a lignin‐based macromonomer, lignocatechol, was carried out for the first time in ethanol–phosphate buffer solvent system to give crosslinked polymers in good yields. Lignocatechol was prepared by the phase separation system of lignin and catechol in aqueous sulfuric acid. The copolymerization was also performed with urushiol to afford the corresponding copolymers in high yields. The polymerization mechanism was estimated by the IR and pyrolysis GC‐MS measurements, suggesting that the polymerization proceeded mainly at the catechol ring through a quinone radical intermediate. The thermal properties were measured by the DSC, TG, and TMA analyses, indicating that the polymers had high thermal stabilities because of the crosslinked structures. In addition, it was found that the resulting polymers had the affinity of bovine serum albumin (BSA) and glucoamylase. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 824–832, 2009 相似文献
147.
We investigated the effects of added oxide to FeSi2 on thermoelectric properties in order to improve the figure of merit. The oxide was not suggested to chemically react with
the mother material (FeSi2), where the oxide materials existed in the grain boundaries. The oxide addition played a role to reduce thermal conductivity
and possessed electrical resistivity as well as non oxide-added FeSi2. Hereafter, the appropriate added amount of Yb2O3 showed the largest effect on the figure of merit among other oxides. 相似文献
148.
Takeshi Ishikawa Yuji Mochizuki Shinji Amari Tatsuya Nakano Shigenori Tanaka Kiyoshi Tanaka 《Chemical physics letters》2008,463(1-3):189-194
We have developed a method named ‘fragment interaction analysis based on local MP2’ (abbreviated as FILM). This method enables us to decompose the interaction energy associated with dispersion interactions into contributions of localized occupied orbitals. In this study, the basis set dependence of the results derived from FILM was examined. The results suggested that the individual ratio of pair correlation energies of selected orbital pairs to the total dispersion interaction was almost independent of the basis set size. As an illustrative example, detailed analysis was performed on the human immunodeficiency virus type 1 protease complexed with lopinavir molecule. 相似文献
149.
We have determined the orientational distribution of cyano-substituted side chains of a rubbed polyimide film, and a liquid crystal monolayer adsorbed on the film, by means of optical second harmonic generation. With the orientational distribution of a main chain that was measured in a previous study by means of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, we have obtained the correlation of all the orientational distributions contributing to the alignment of LC molecules, i.e. pretilt angle. We find that the side chain plays a role in increasing the pretilt angle, but in the case of rubbing strength dependence, the main chain has stronger correlation with the pretilt angle than has the side chain. 相似文献