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31.
Yoshiki Chujo Akio Naka Martina Krämer Kazuki Sada Takeo Saegusa 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):1213-1223
Abstract This paper describes the synthesis of various star-shaped polymers by means of complexation of bipyridyl-terminated polyoxyethylene with Ru(II) ion. Three kinds of bipyridyl-terminated polyoxyethylenes of different molecular weights were prepared from the corresponding polyoxyethylene monomethyl ethers with narrow molecular weight distributions. Bipyridyl was found to be introduced quantitatively at the end of the polymers based on the results of UV spectra. The formation of a star-shaped polymer was carried out by the reaction of RuCl3 with three equivalents of bipyridyl-terminated polyoxyethylene. The UV spectrum of the star-shaped polymer obtained supported the formation of a typical Ru(II) tris(bipyridyl) complex. From the results of GPC, the star-shaped polymer obtained had a higher molecular weight than the pre-polymer and showed a narrow molecular weight distribution. In the case of a Ni(II) or a Co(II) complex, however, the star-shaped polymer was found to be dissociated into three linear prepolymers under the conditions of GPC measurement. 相似文献
32.
Takeo Saegusa 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):997-1026
Abstract In the present series of studies on the cationic polymerization of cyclic ethers, the reactivities of cyclic ethers were quantified and the effect of the catalyst upon the polymerization kinetics was revealed. These kinetic analyses were successfully performed by means of our “phenoxyl end-capping method”. The change of the reactivity by the ring size of the monomer was interestingly demonstrated. In addition, it is emphasized that the frequency factor as well as the activation energy influence the rate constant of propagation. As to the effect of catalyst upon the polymerization kinetics, the most important conclusion is that the rate constant of propagation changes very little according to the changes of the catalyst components. Variation of the conversion rate by a change of catalyst is due to differences in the rates of the initiation and the termination reactions. 相似文献
33.
Novel methods of synthesis of spiro acyloxyphosphoranes are described emphasizing the significance of the first isolated instance of these new species. Then, the no-catalyst alternating copolymerizations of the combinations of cyclic phosphorus(III) compounds (serving as nucleophilic monomer, MN) with acrylic acid derivatives and with α-keto acids (electrophilic monomer, ME) are mentioned. These copolymerizations proceed without added initiator. Spiro oxyphosphoranes play an important role in the copolymerization scheme in the equilibrium with the +MN - ME ? zwitterion, the key intermediate of the copolymerization. Finally, new reactions of spiro acyloxyphosphoranes with nucleophiles, alcoholysis and aminolysis polymerizations are presented. 相似文献
34.
Noboru Oyama Takeo Ohsaka Fumihiro Yoshimura Masaya Mizunuma Shuichiro Yamaguchi Norihiko Ushizawa 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10-11):1463-1473
The electrode characteristics of ion-selective electrodes (ISEs) for K+, Na+, NH4 +, and Ca2+ based on bilayer film coatings, where the inner layer films are electroactive electropolymerized ones and the outer layer films are composed of conventional ion-sensitive materials, have been examined. These ISEs of the coated-wire electrode type have no conventional internal reference solution and reference electrode, but the inner films may be considered to function as the “internal standard solution.” The ion selectivity coefficients and the activity range showing Nernstian response were almost comparable to those of conventional liquid-membrane electrodes. The bilayer-coated ISEs showed insensitivity to O2 and CO2, long-term stability, and little drift. It was also found that the electrode performance is practically unchanged after sterilization in an autoclave. The results demonstrate that the bilayer-coated ISEs examined are promising for the determination of K+, Na+, NH4 +, or Ca2+ activity in biological and environmental systems. 相似文献
35.
We have recently found that the reaction of α-keto acids (1) with phosphorus (III) compounds (3) yielded cyclic acyloxyphosphoranes(C-AOPs, 4), a new class of pentacovalent phosphorus species having a P-OC(O) group.1, 2) The present paper deals with a new reaction of glyoxylic acid (2) with 3 to give C-AOPs (5) having no substituent at the C-3 position. 1 is an α-keto acid whereas 2 can be taken as an α-formyl acid. Although it is well known in the field of organic chemistry that the formyl group often behaves differently from a keto group, the reaction of 2 with 3 provides an example in which both groups behave in a similar manner. 相似文献
36.
Kenichi Takeo Kimiko Nagayoshi Kenichi Nishimura Shinichi Kitamura 《Journal of carbohydrate chemistry》2013,32(8):1159-1177
Abstract The 8-methoxycarbonyloctyl β-glycosides of the trisaccharides O-β-d-Glcp-(1 → 6)- O-β-d-Glcp-(1 → 3)-d-Glcp and O-β-d-Glcp-(1 → 3)-O-[β-d -Glcp-(1 → 6)]-d-Glcp and of the tetrasaccharide O-β-d-Glcp-(1 → 3)-O-[β-d-Glcp-(1 → 6)]-O-β-d-Glcp-(1 → 3)-d-Glcp, corresponding to the fragments of schizophyllan, have been synthesized by using mono- to tetrasaccharide 1-thioglycosides as glycosyl donors, each bearing a participating benzoyl group in the 2-position, and N-iodosuccinimide and silver triflate as promoter. Saponification of the tri- and tetrasaccharide β-glycosides, followed by attachment to bovine serum albumin of the resulting sugar derivatives having a carboxyl group at the aglycon terminal, provided neoglycoproteins for immunological studies of the polysaccharide. 相似文献
37.
Miyauchi Suguru Yamada Shuji Takeuchi Shintaro Tazaki Asahi Kajishima Takeo 《Transport in Porous Media》2022,141(1):185-199
Transport in Porous Media - A concise and accurate prediction method is required for membrane permeability in chemical engineering and biological fields. As a preliminary study on this topic, we... 相似文献
38.
应用电化学法聚合酚藏花红(PPS)功能化的单壁碳纳米管,以其作为烟酰胺辅酶(NADH)氧化的电化学催化剂(电极),构建基于乙醇脱氢酶的安培型乙醇生物电化学传感器.该电极于0.0 V时,对NADH具有很好的催化性能.而单体酚藏花红则由于其电位过低(-0.48 V),不能显示催化性能.循环伏安和计时安培法测试表明:该传感器... 相似文献
39.
电化学氧化增强金属钴卟啉的自组装研究 总被引:1,自引:0,他引:1
应用电化学方法将钴(Ⅱ)卟啉氧化成钴(Ⅲ)卟啉以增强它与4-巯基吡啶(MP)自组装膜的轴向配位作用,从而快速制备了有序钴卟啉自组装修饰电极CoTMPP/MP/Au(E).电化学石英晶体微天平(EQCM)测试证实电化学氧化对钴卟啉膜生长过程的增强作用.Ram an光谱及修饰电极电催化还原氧研究显示,该修饰电极与经过长时间浸渍法得到的CoTMPP/MP/Au(I)修饰电极具有完全相似的有序结构和性质.与直接将钴卟啉吸附在电极表面的CoTMPP/Au修饰电极相比,以巯基吡啶为桥键得到的钴卟啉修饰电极具有更好的电催化活性和稳定性. 相似文献
40.
Takeo MoroiKazunori Nakayama 《Physics letters. [Part B]》2011,703(2):160-166
Thermal inflation is an attractive solution to the cosmological moduli problem. However, domain walls may be formed after thermal inflation and some mechanisms are needed to eliminate the domain wall before it dominates the Universe. We point out that gravitational waves produced by the dynamics of domain walls may be observed by the pulsar timing experiments and future space-borne gravitational wave detectors, which provides a probe into the period of thermal inflation. We also show that the QCD instanton effect can effectively eliminate the domain walls with producing observable amount of gravitational waves. 相似文献