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191.
192.
Metal-ion complexation of 7-benzylimidazo[1,2-a]pyrazin-3(7H)-one derivative (2) with Li+, Mg2+, Ca2+, Ba2+, Sc3+, and La3+ in acetonitrile resulted in successive modulations of its UV/vis absorption and fluorescence spectroscopic properties. This result indicates that 2 can be used as a colorimetric and fluorometric sensor of the Lewis acidity of a metal ion in aprotic solutions. The hypothesis that the metal-ion complex has a O10(imidazopyrazinone)-metal ion bond was supported by X-ray crystallographic analysis and quantum chemical calculations for a Li+ complex of 7-methylimidazo[1,2-a]pyrazin-3(7H)-one derivative (1). 相似文献
193.
Yoshida T Nishi I Ideta S Fujimori A Kubota M Ono K Kasahara S Shibauchi T Terashima T Matsuda Y Ikeda H Arita R 《Physical review letters》2011,106(11):117001
We have studied the three-dimensional shapes of the Fermi surfaces (FSs) of BaFe(2)(As(1-x)P(x))(2) (x=0.38), where superconductivity is induced by isovalent P substitution and by angle-resolved photoemission spectroscopy. Moderately strong electron mass enhancement has been identified for both the electron and hole FSs. Among two observed hole FSs, the nearly two-dimensional one shows good nesting with the outer two-dimensional electron FS, but its orbital character is different from the outer electron FS. The three-dimensional hole FS shows poor nesting with the electron FSs. The present results suggest that the three dimensionality and the difference in the orbital character weaken FS nesting while partial nesting among the outer electron FSs of d(xy) character and/or that within the three-dimensional hole FS becomes dominant, which may lead to the nodal superconductivity. 相似文献
194.
T. Ino Y. ArimotoT. Yoshioka K. MishimaK. Taketani S. MutoH.M. Shimizu H. KiraY. Sakaguchi T. OkuK. Sakai T. ShinoharaJ. Suzuki H. OtonoH. Oide S. YamashitaS. Imajo H. FunahashiM. Yamada Y. IwashitaM. Kitaguchi M. HinoZ. Suzuki T. SanukiT. Seki K. HirotaK. Ikeda H. SatoY. Otake H. OhmoriT. Morishima T. Shima 《Physica B: Condensed Matter》2011,406(12):2424-2428
We measured the neutron beam polarization of the BL05/NOP (Neutron Optics and Physics) beamline at J-PARC with an accuracy of less than 10−3 using polarized 3He gas as a neutron spin analyzer. Precise polarimetry of the neutron beam is necessary to understand the beamline optics as well as for the asymmetry measurements of the neutron beta decay, which are planned in this beamline. 相似文献
195.
Naofumi Naga Takeshi Shiono Tomiki Ikeda 《Journal of molecular catalysis. A, Chemical》1999,150(1-2):155-162
Ethylene polymerization was conducted with bis(cyclopentadienyl)zirconium dichloride (1) and rac-dimethylsilylenebis(indenyl)zirconium dichloride (2) combined with trialkylaluminum (AlR3; R=methyl (Me), ethyl (Et), isobutyl (iBu))/triphenylcarbenium tetrakis(pentafluorophenyl)borate (Ph3CB(C6F5)4) or tris(pentafluorophenyl)borane (B(C6F5)3) to study the effect of cocatalysts on polymerization rate (Rp). When AlMe3 was used, no activity or very low activity was observed with both zirconocenes regardless of the borane compounds used. The replacement of AlMe3 to AlEt3 or AliBu3 with 1–AlR3/Ph3CB(C6F5)4 caused polymerization and induction time was observed to reach the maximum Rp. Especially in the case of using AlEt3, it took about 30 min to show the activity. When B(C6F5)3 was used, AlEt3 was not effective but AliBu3 gave the highest activity among all the combinations of AlR3 and the borane compounds. In the case of polymerization with 2 using Ph3CB(C6F5)4, high activity was observed with both AlEt3 and AliBu3 without any induction period. When B(C6F5)3 was used instead of Ph3CB(C6F5)4, very low activity was observed with AlEt3. On the other hand, high activity was observed with AliBu3, and the maximum Rp was found at the beginning of the polymerization. The effect of AlR3 on the formation of active species was discussed based on these results. 相似文献
196.
197.
Maria Carmelita Z. Kasuya Maki Ikeda Kazuhiko Hashimoto Toshinori Sato 《Journal of carbohydrate chemistry》2013,32(7):705-715
The synthesis of sialylated glycosides using saccharide primers and cells was investigated. α · and β · Saccharide primers were chemically synthesized and introduced into B16 melanoma cells to prime oligosaccharide synthesis. Incorporation of α‐ and β‐dodecyl lactosides into B16 cells resulted in the sialylation of the galactose residue to give GM3‐type oligosaccharides. The β‐dodecyl galactoside primer was sialylated but the α‐dodecyl galactoside primer was not. Both the α‐ and β‐dodecyl glucoside primers were not elongated. In the glycosylation of primers by cells, this research confirmed that sialyl transferases tolerate acceptor modifications and are permissive to primer elongation regardless of the α‐ or β‐linkage to the aglycon unit. However, the presence of the terminal galactose residue that is β‐linked to the adjacent saccharide or aglycon unit is essential for sialylation by cellular enzymes to occur. 相似文献
198.
Chisato Katahira Nobuya Morishita Jun‐Ichi Ikeda Pang Boey Lim Mitsuteru Inoue Yuri Iwasaki Hiroyuki Aota Akira Matsumoto 《Journal of polymer science. Part A, Polymer chemistry》2010,48(20):4445-4455
Our previous mechanistic discussion of the free‐radical crosslinking monoallyl/diallyl copolymerizations was extended to the cationic crosslinking monoepoxide/diepoxide copolymerizations, typically including 1,2‐epoxycyclohexane (ECH) as a monoepoxide and bis[3,4‐epoxycyclohexylmethyl] adipate (BECHMA) as a diepoxide crosslinker. In the cationic polymerization, oligomer is usually obtained because of the occurrence of characteristic chain‐forming reactions. Therefore, cationic crosslinking monoepoxide/diepoxide copolymerizations could be in the category of the network formation through free‐radical crosslinking monoallyl/diallyl copolymerizations. Thus, the gelation behavior was discussed by comparing the actual gel points with the theoretical ones; the greatly delayed gelation from theory was observed. Then, the resulting network polymer precursors (NPPs) were characterized by SEC‐MALLS‐viscometry to clarify the cationic crosslinking ECH/BECHMA copolymerization mechanism. Notably, the correlation lines of molecular weight versus elution volume were specific for the NPPs obtained at a high conversion close to the gel point as compared with those obtained by the free‐radical crosslinking monoallyl/diallyl copolymerization. This may be ascribed to the occurrence of intramolecular and intermolecular chain transfer reactions characteristic of cationic polymerization; the chain transfer reactions involve the intramolecular and intermolecular nucleophilic attack of ether oxygen or terminal hydroxyl oxygen in the NPPs to a terminal growing cation that leads to the formation of not only the loop‐ but also the crosslink‐structures containing NPPs, providing fragile ultrahigh‐molecular‐weight NPP in the SEC columns. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
199.
Gang Dai Yoshikazu Ohno Yoichi Ikeda Jun Tamogami Takashi Kikukawa Naoki Kamo Tatsuo Iwasa 《Photochemistry and photobiology》2010,86(3):571-579
Phoborhodopsin (pR; also called sensory rhodopsin II, SRII) is a photoreceptor of negative phototaxis of halobacteria. The studies of photochemical properties of this pigment are not many because the amount of the pigment is small and the stability is low. Recently an expression system of phoborhodopsin from Halobacterium salinarum (called salinarum phoborhodopsin, spR; also HsSRII) in Escherichia coli and purification method has been developed (Mironova et al. [2005] FEBS Lett., 579, 3147–3151), which enables detailed studies on the photochemical properties of spR. In the present work, the photoreaction cycle of E. coli-expressed spR was studied by low-temperature spectroscopy and flash photolysis. Formations of K-, M-, O-like intermediates and P480 were reconfirmed as reported previously. New findings are as follows. (1) The K-like intermediate (P500) was a mixture of two photoproducts. (2) Formation of L-like intermediate (P482) was observed by low-temperature spectroscopy and flash photolysis at room temperature. (3) On long irradiation of spR at 20°C, formation of a new photoproduct P370 was observed and it decayed to the original spR in the dark with a decay half time of 190 min. Based on these results the similarities and dissimilarities between spR and ppR are discussed. 相似文献
200.
A simple and efficient total synthesis of ellipticine was developed via the Suzuki-Miyaura coupling of sterically sensitive 2-hydroxybenzeneboronic acid with a multifunctional aryl halide using Pd(OAc)2 as a catalyst and Cu(OAc)2·H2O as an additive in DMSO/H2O as a key step followed by double N-arylation and cyclization. 相似文献