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991.
Jun Akimitsu Jiro Amano Masaki Yoshinari Michio Kokubun Tatsuya Iwasaki Satoshi Okuma Nobuhiko Nishida Kusuo Nishiyama Nobuo Mori 《Hyperfine Interactions》1994,85(1):187-192
We report SR measurements of Pr2CuO4– and (Pr2–xCex)CuO4– single crystals in the temperature range 4.2K300K. Two spin reorientation phase transitions were observed, although neutron scattering experiment could not detect these phase transitions. These allow us to conclude that magnetic moments of the Cu atoms order in an antiferromagnetic noncollinear cross like structure including a hidden canting spin arrangement. 相似文献
992.
Itsuo Mori Takako Matsuo Yoshikazu Fujita Minako Toyoda Kenichi Ichitani Noriko Inoue 《Fresenius' Journal of Analytical Chemistry》1994,348(5-6):346-349
Summary A spectrofluorophotometric determination of thallium(III) is proposed. It is based on the enhancement of the fluorescence reaction of 3,4,5,6-tetrachlorofluorescein (TCF) with Pyrogallol Red (PR) by thallium(III) in the presence of Swanol (AM 301, lauryldimethyl aminoacetic acid betain) as an amphoteric surfactant. The method was found to be suitable for the determination of thallium(III) down to 4.0 g in 10.0 ml by measuring the difference in the relative fluorescence intensities of a TCF/PR/thallium(III) solution and a TCF/PR solution. The recovery test in artificial urine was satisfactory (96±2%). 相似文献
993.
Tsutomu Kumagai Takumi Nittono Noriyuki Tanaka Toshio Mukai 《Tetrahedron letters》1985,26(49):6093-6096
Upon irradiation, 2-dicyanomethylenebenzonorbornene f was converted into 1-dicyanomethylenebenzobicyclo[3.1.1]heptene . The reaction pathway is discussed with reference to the photoreaction of parent hydrocarbon. 相似文献
994.
Takehisa Hanawa Etsuo Yonemochi Toshio Oguchi Yoshinobu Nakai Keiji Yamamoto 《Journal of inclusion phenomena and macrocyclic chemistry》1993,15(1):91-101
Characterization of an inclusion complex prepared from amorphous ground mixtures of heptakis (2,6-di-O-methyl)--cyclodextrin (DMCD) and benzoic acid was carried out by a sealed heating method. The formation of the crystalline inclusion complex and the variation in physicochemical properties of the ground mixture were investigated as a function of heating temperature. On the basis of X-ray diffractometry and Fourier transform infrared spectroscopy, the crystallization of the ground mixture was confirmed to take place at about 135°C. The crystallization temperature was shifted to lower temperatures and the bound molar ratio of benzoic acid to DMCD increased as the mixing molar ratio of benzoic acid to DMCD was raised.Tsumura & Co., 3586 Yoshiwara, Amimachi, Inashikigun, Ibaraki 300-11, Japan. 相似文献
995.
(1R,5S,7S)-(+)-endo-Brevicomin (7-ethyl-5-methyl-6,8-dioxabicyclo[3.2.1]octane) and its (1S,5R),7(R)-(?)-isomer were synthesised employing the Sharpless asymmetric epoxidation as the key-step. 相似文献
996.
Jiro Motoyoshiya Akira Takagi Kiyoichi Hirakawa Toshio Kakurai 《Journal of heterocyclic chemistry》1986,23(2):597-599
Several ketenimines bearing ester groups were prepared and their thermal reactions gave 2-alkoxy-3-substituted-4-quinolinols VIa-e via presumed iminoketene intermediates. Subsequent oxidation of 2-alkoxy-3-(3-methylbut-2-enyl)-4-quinolinols VIc and VId provided pyranoquinolines VIIIa and VIIIb. 相似文献
997.
1-Chloro-2-methyl-N,N-tetramethylenepropenylamine was found to be an efficient condensation reagent for the regioselective coupling reaction of propargyl alcohols with Grignard reagents to give allenes in good yields with high chemo- and enantioselectivities. The utility of the reaction was demonstrated in the stereocontrolled synthesis of methyl (E)-2,4,5-tetradecatrienoate, the pheromone of the male dried bean beetle. 相似文献
998.
Iwao?KatayamaEmail author Yoshihiro?Suzuki Yoshiaki?Yamamoto Toshio?Oishi 《Monatshefte für Chemie / Chemical Monthly》2005,136(11):1955-1961
Summary. The EMF of galvanic cells with stabilized zirconia solid electrolyte was measured to determine the activity of indium in solid
Ni–In alloys in the temperature range of 970–1170 K and composition range of 5–55 mol% In. Activity of indium increases sharply
in the ζ phase and Ni13In9 phase. The activity values are compared with literature data. 相似文献
999.
Kiyoshi Sawada Misao Kuribayashi Toshio Suzuki Hiroshi Miyamoto 《Journal of solution chemistry》1991,20(8):829-839
The protonation equilibria of nitrilotris(methylenephosphonic acid) (NTMP, H6L) and ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP, H8L) complexes of scandium, yttrium, and lanthanoids have been studied potentiometrically at 25°C and at an ionic strength of 0.1 mol-dm–3 KNO3. The first protonation constants of NTMP complexes of lanthanoids, K
MHL
, decrease with decreasing of the ionic radius of the lanthanoid [log K
MHL
=7.82 (La3+) –6.90 (Lu3+)] and show a so-called Tetrad effect. The second protonation constants, K
MH
2L, change very little with the lanthanoid metal ions (logK
MH
2L=5.3–5.7). These results suggest that, in the first protonation process in ML, the proton attacks the nitrogen of NTMP rupturing the M-N of M(ntmp)3–. The pattern of the change in the protonation constants of the EDTMP complexes with the atomic number of the lanthanoid is quite different from that of the NTMP complexes. This fact indicates that the manner of protonation of the EDTMP complexes differs from that of NTMP complexes. The protonation constants of yttrium complexes of NTMP and EDTMP agree with those of lanthanoid complexes, whereas those of scandium complexes deviate from the values predicted from its ionic radius. 相似文献
1000.
Structure and reactivity in cationic polymerization of butadiene derivatives. IV. 1-alkoxybutadienes
Michihisa Otsuki Toshio Masuda Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1976,14(5):1157-1166
The reactivity of trans-1-alkoxybutadienes in cationic homopolymerization and copolymerizations and structure of the polymers produced were investigated. 1-Ethoxybutadiene is polymerized easily at ?78°C by various acidic catalysis. The reactivity of 1-ethoxybutadiene was similar to that of ethyl vinyl ether. The polymers produced possessed molecular weights of several thousands, and were composed of 70–95% 1,4 structure and 5–30% 3,4 structure. In the copolymerization of ethyl vinyl ether (M1) with 1-ethoxybutadiene at ?78°C in toluene by boron trifluoride diethyl etherate, r1 = 1.15, r2 = 2.62. From the Hammett plot of the relative reactivities of alkoxybutadienes (alkoxy: CH3O, C2H5O, i-C3H7O), the reaction constant p* was determined to be ?2.9. Results of the present study were compared with those of various butadiene derivatives. 相似文献