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排序方式: 共有135条查询结果,搜索用时 31 毫秒
71.
Hisanori Sugiura Yoshiaki Saklrai Yoshihide Masuda Hitoshi Takeda Shigekazu Kusabayashi Shunsuke Takenaka 《Liquid crystals》2013,40(3):441-450
Abstract The thermal properties of 4-octyloxyphenyl 4-(4-R-3-nitrobenzoyloxy) benzo-ates (1) and 4-(4-octyloxybenzoyloxy)phenyl 4-R-3-nitrobenzoates (2) have been examined, where R = hydrogen, halogens, alkyl and alkoxy groups. The derivatives of compound 1 incorporating hydrogen, halogens, methoxy and nitro groups show a smectic A phase having a bilayer arrangement, and the others with a long alkoxy group show the SA phase with the monolayer arrangement. The derivatives of compound 2 incorporating halogens, and the nitro group show the SA phase with the monolayer arrangement. The alkoxy derivatives show a smectic C phase as well as the nematic phase. The nitro group at the lateral position tends to increase the ratio of the SA-N transition temperature to the N-I. The effect of the nitro group on the smectic properties has been discussed in terms of the structural and electrostatic nature of the nitro group. 相似文献
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73.
Yuanlai Xu Seong-Yun Kim Tatsuya Ito Keitaro Hitomi Etsushu Kuraoka Shigekazu Usuda Keizo Ishii 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):149-155
To separate minor actinides from high level liquid waste (HLLW) of PUREX reprocessing, a silica-based macroporous isobutyl-BTP/SiO2-P adsorbent was synthesized by impregnating isobutyl-BTP (2,6-di(5,6-diisobutyl-1,2,4-triazin-3-yl)pyridine) extractant into the macroporous SiO2-P support with a mean diameter of 60 μm. A partitioning process using extraction chromatography for the treatment of HLLW was designed consisting five separation columns. As a partly work focused on isobutyl-BTP/SiO2-P separation column, adsorption behavior of 241Am and trivalent rare earth (RE) from simulated HLLW onto silica-based isobutyl-BTP/SiO2-P adsorbent was investigated by batch method. Meanwhile, the chemical and radiolytic stabilities of isobutyl-BTP/SiO2-P adsorbent against 0.01 M HNO3 solution and γ-ray irradiation were studied. It was found that isobutyl-BTP/SiO2-P adsorbent exhibited good adsorption selectivity for 241Am over RE(III) in 0.01 M HNO3 solution and showed weak or no adsorption affinity to light and middle RE(III) groups. In addition, in stability experiments, isobutyl-BTP adsorbent showed excellent stability against 0.01 M HNO3 solution and γ-ray irradiation over 4 months contact time. 相似文献
74.
Paradigm Shift from Alkaline (Earth) Metals to Early Transition Metals in Fluoroorganometal Chemistry: Perfluoroalkyl Titanocene(III) Reagents Prepared via Not Titanocene(II) but Titanocene(III) Species
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Motohiro Fujiu Ryota Hashimoto Yuzo Nakamura Prof. Dr. Kohsuke Aikawa Prof. Dr. Shigekazu Ito Prof. Dr. Koichi Mikami 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2382-2386
Perfluoroalkyl (RF) titanocene reagents [Cp2TiIIIRF] synthesized via [Cp2TiIIICl] rather than [Cp2TiII] show new types of perfluoroalkylation reactions. The [Cp2TiIIIRF] reagents exhibit a wide variety of reactivity with carbonyl compounds including esters and nitriles, and selectivities far higher than those reported for conventional RFLi and RFMgX reagents. 相似文献
75.
Yuanlai Xu Seong-Yun Kim Shigekazu Usuda Yuezhou Wei Keizo Ishii 《Journal of Radioanalytical and Nuclear Chemistry》2013,297(1):91-96
To understand the separation behavior of Zr(IV) in the partitioning process for high level liquid waste, a silica-based macroporous adsorbent (TODGA/SiO2-P) was prepared by impregnating N,N,N′,N′-tetraoctyl-3-oxapentane-1,5-diamide (TODGA) into a macroporous silica/polymer composite particles support (SiO2-P). Adsorption and desorption behavior of Zr(IV) from nitric acid solution onto silica-based TODGA/SiO2-P adsorbent were investigated by batch experiment. It was found that TODGA/SiO2-P showed strong adsorption affinity to Zr(IV) and this adsorption process reached equilibrium state around 6 h at 298 K. Meanwhile, HNO3 concentration had no significant effect on the adsorption of Zr(IV) above 1 M. From calculated thermodynamic parameters, this adsorption process could occur spontaneously at the given temperature and was confirmed to be an exothermic reaction. This adsorption process could be expressed by Langmuir monomolecular layer adsorption mode and the maximum adsorption capacity were determined to be 0.283 and 0.512 mmol/g for Zr(IV) at 298 and 323 K, respectively. In addition, more than 90 % of Zr(IV) adsorbed onto adsorbent could be desorbed with 0.01 M diethylenetriamine pentaacetic acid solution within 24 h at 298 K. 相似文献
76.
Ogino M Fukui S Nakada Y Tokunoh R Itokawa S Kakoi Y Nishimura S Sanada T Fuse H Kubo K Wada T Marui S 《Chemical & pharmaceutical bulletin》2011,59(10):1268-1273
Acyl-CoA: cholesterol acyltransferase (ACAT) is an intracellular enzyme that catalyzes cholesterol esterification. ACAT inhibitors are expected to be potent therapeutic agents for the treatment of atherosclerosis. A series of potent ACAT inhibitors based on an (4-phenylcoumarin)acetanilide scaffold was identified. Evaluation of the structure-activity relationships of a substituent on this scaffold, with an emphasis on improving the pharmacokinetic profile led to the discovery of 2-[7-chloro-4-(3-chlorophenyl)-6-methyl-2-oxo-2H-chromen-3-yl]-N-[4-chloro-2-(trifluoromethyl)phenyl]acetamide (23), which exhibited potent ACAT inhibitory activity (IC50=12 nM) and good pharmacokinetic profile in mice. Compound 23 also showed regressive effects on atherosclerotic plaques in apolipoprotein (apo)E knock out (KO) mice at a dose of 0.3 mg/kg per os (p.o.). 相似文献
77.
Yo Shimizu Kunio Shigeta Shigekazu Kusabayashi 《Molecular Crystals and Liquid Crystals》2013,570(2-4):105-117
The mesomorphic properties of 2-(2-hydroxy-4-alkoxybenzylideneamino)-9-methyl-carbazoles were investigated and the photoconducting behavior of the crystalline, nematic and isotropic liquid phases were compared for the pentyloxy compound. It was found that the behavior in the nematic phase is comparable with that in the isotropic liquid phase, both being fluid, rather than that in the crystalline phase. The carrier transport mechanisms and the carrier species are implied to be ionic. The current-voltage characteristics showed a new behavior in the fluid states, being similar to that of the negative resistance. 相似文献
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79.
Reactions of sterically protected 2-bromo-3-phenyl-1-phosphapropenes with bases such as tert-butyllithium and potassium tert-butoxide successfully afforded a bulky 1,4-diphosphafulvene (Mes = 2,4,6-tBu(3)C(6)H(2)) through a novel and formal dimerization pathway of 1-phosphaallene, together with small amounts of 3-phenyl-1-phosphaallene and 3,4-diphosphanylidenecyclobutene. The structure of the 1,4-diphosphafulvene was confirmed by X-ray crystallography indicating somewhat flattened phosphorus atoms due to the bulky Mes groups. The electrochemical properties of the 1,4-diphosphafulvene were investigated to show promising suitability as an electron donor, and indeed, it afforded a charge-transfer complex with TCNQ. Preparation and structural elucidation of an alkoxy-functionalized 1-phosphaallene was also performed, and the effect of the alkoxy group on the 1-phosphaallene moiety was characterized. 相似文献
80.
[reaction: see text] 2-Methyl-3,3-diphenyl-3-thioxo-1-(2,4,6-tri-tert-butylphenyl)-1,3-diphosphapropene, which bears a P=C-P=S skeleton, was prepared and used as a ligand of transition-metal complexes. The palladium complexes containing the ligated 3-thioxo-1,3-diphophapropene were stable and used for catalytic reactions such as cross-couplings and direct conversion of allyl alcohol to allylaniline. 相似文献