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41.
硫化钼是析氢反应(HER)有前途的电催化剂.S-或Mo物种均被认为是形成吸附氢触发HER反应的活性位,但Mo中心和S配体间相互作用的本质仍不清楚.另外,采用中性的水作为质子源用于产氢,来开发低成本的水裂解催化剂体系为研究者高度关注,但人们很少研究中性水条件下HER反应的机理.本文采用原位电化学Raman光谱对所合成的硫化钼中Mo–Mo和S–S物种在中性条件下的结构变化进行了监测.结果显示,归属于端位S–S物种的谱带随着和Mo–S振动谱带频率而同步变化,表明Mo–Mo键与端位S–S键起着协同作用,从而有利于氢气的生成.这可能是通过三核物种的内部重组而确认的.本文所揭示的HER反应中金属-配体相互作用的本质与作用表明了一个不同的反应机理,而以往的机理认为,S或Mo活性位独立起作用而促进HER反应的进行. 相似文献
42.
K. Yano 《SAR and QSAR in environmental research》2013,24(1):15-26
Abstract A method for a preliminary survey of the relationship between molecular structure and performance was described using 1506 random data of structure-acute toxicity for mice (intravenously dosed). The structural patterns of the weakest toxic structures (111) were extracted from the data and the patterns discriminated for 64.2% of the other structures (1395). As for the 826 structures of strongest toxicity, 78.3% were discriminated by these structural patterns. These results were obtained by using structural parameter ratios to describe the structural patterns and the exhaustive elimination process to select the best parameter ratio from many candidates. The results were summarized in the form of a chart which can be used for practical screening for the weakest toxic structures. 相似文献
43.
A validated LC‐MS/MS method for the determination of canagliflozin,a sodium–glucose co‐transporter 2 (SGLT‐2) inhibitor,in a lower volume of rat plasma: application to pharmacokinetic studies in rats 下载免费PDF全文
Shinji Kobuchi Kyoka Yano Yukako Ito Toshiyuki Sakaeda 《Biomedical chromatography : BMC》2016,30(10):1549-1555
Canagliflozin is a novel, orally selective inhibitor of sodium‐dependent glucose co‐transporter‐2 (SGLT2) for the treatment of patients with type 2 diabetes mellitus. In this study, a validated liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method for the quantitative analysis of canagliflozin in a lower volume of rat plasma (0.1 mL) was established and applied to a pharmacokinetic study in rats. Following liquid–liquid extraction by tert‐butyl methyl ether, chromatographic separation of canagliflozin was performed on a Quicksorb ODS (2.1 mm i.d. × 150 mm, 5 µm size) using acetonitrile–0.1% formic acid (90:10, v/v) as the mobile phase at a flow rate of 0.2 mL/min. The detection was carried out using an API 3200 triple‐quadrupole mass spectrometer operating in the positive electrospray ionization mode. Selected ion monitoring transitions of m/z = 462.0 [M + NH4]+ → 191.0 for canagliflozin and m/z = 451.2 [M + H]+ → 71.0 for empagliflozin (internal standard) were obtained. The validation of the method was investigated, and it was found to be of sufficient specificity, accuracy and precision. Canagliflozin in rat plasma was stable under the analytical conditions used. This validated method was successfully applied to assess the pharmacokinetics of canagliflozin in rats using 0.1 mL rat plasma. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
44.
45.
Masayuki Kirihara Takuya Noguchi Nobuhiro Okajima Sayuri Naito Yuki Ishizuka Aiko Harano Hiroyuki Tsukiji Ryu Takizawa 《Tetrahedron》2012,68(5):1515-1520
The reaction of dithioacetals with 30% hydrogen peroxide in the presence of catalytic amounts of tantalum(V) and iodide ion effectively produced carbonyl compounds in high yields. Dithioacetals also can be deprotected using the niobium(V) catalyzed oxidation of iodide ion by hydrogen peroxide under mild conditions. 相似文献
46.
Stochastic equations indexed by negative integers and taking values in compact groups are studied. Extremal solutions of the equations are characterized in terms of infinite products of independent random variables. This result is applied to characterize several properties of the set of all solutions in terms of the law of the driving noise. 相似文献
47.
A new diarylheptanoid glucoside,(8R,9R)-17-methoxy-2-oxatricyclo[13.2.2.13.7]icosa-l(17),3(20),4,6, 15,18-hexaene-4,9,10-triol-9-O-β-D-glucopyranoside(1),namely jugcathayenoside,together with two known diarylheptanoids,(+)-galeon(2) and 4-hydroxy-17-methoxy-2-oxatricyclo[13.2.2.13,7 ]icosa-1(17),3(20),4,6,15,18-hexaene-9-one(3),were isolated from the root bark of Juglans cathayensis. Their structures were elucidated on the basis of extensive spectroscopic data analysis. 相似文献
48.
An efficient and mild synthesis of 2-(guaiazulen-1-yl)furans,starting from easily accessible 1-(3-aryl-2-cyanopropenoyl) guaiazulenes,tributylphosphine and acyl chlorides,is described.The strategy employs the intramolecular Wittig protocol as a key step to append the crticial furan ring,leading to the highly functional furans in good yields. 相似文献
49.
Lan Yu Qi Wang Lu Dai Wei-Ying Li Rong Chen Mian HR Mahmood Hai-Yang Liu Chi-Kwong Chang 《中国化学快报》2013,24(6):447-449
Pseudo-first order reaction rate constants of 5,10,15-tris(pentafluorophenyl)corrole Mn(V)-oxo (F15CMn(V)-oxo),5,15-bis(pentafluorophenyl)-10-(phenyl)corrole Mn(V)-oxo(F10CMn(V)-oxo),5,15- bis(phenyl)-10-(pentafluorophenyl)corrole Mn(V)-oxo(F5CMn(V)-oxo) and 5,10,15-tris(phenyl)corrole Mn(V)-oxo(F0CMn(V)-oxo) with a series of alkene substrates in different solvents were determined by UV-vis spectroscopy.The results indicated that the oxygen atom transfer pathway between Mn(V)-oxo corrole and alkene is solvent-dependent. 相似文献
50.
Unmodified and SiCl4-modified spherical zirconia-supported methylaluminoxane were used as cocatalyst for propylene polymerization as well as ethylene/1-hexene copolymerization in combined with Me2Si(η3-C13H8)(η1-NtBu)TiMe2 (1) at 0 °C. The modification with SiCl4 improved the catalytic activity. The improvement was clearer in ethylene/1-hexene copolymerization than in propylene polymerization. The number average molecular weight (Mn) of polypropylenes increased linearly against the polymerization time regardless the cocatalyst used to give polymers with narrow molecular weight distribution (Mw/Mn < 1.32), indicating the living nature of the catalytic systems. Thus, propagation rate constant (kp) and the number of active centers (C*) were evaluated from Mn and the number of polymer-chains. When the zirconia was modified with SiCl4, the kp value decreased and the C* increased. The latter effect was more significant to enhance the catalytic activity. 相似文献