The preparation and some reactions of 2, 3, 5, 6-tetrachlorophenylmagnesium chloride

The reaction of pentachlorobenzene with metallic magnesium in THF at 10–15°C gives after hydrolysis 1, 2, 4, 5-tetrachlorobenzene (76%) and pentachlorobenzene (8%); after trimethylsilylation, 1, 2, 4, 5-tetrachloro-3-(trimethylsilyl)benzene (74%), pentachloro(trimethylsilyl)benzene (8%) and 1, 2, 4, 5-tetrachlorobenzene (6%); after iodination, 1, 2, 4, 5-tetrachloroiodobenzene (44%), pentachloroiodobenzene (12%) and 1, 2, 4, 5-tetrachlorobenzene (9%); and finally after carbonation, 2, 3, 5, 6-tetrachlorobenzoic acid (58%). These products indicate that in the Grignard reaction a mixture of largely 2, 3, 5, 6-tetrachlorophenylmagnesium chloride and some pentachlorophenylmagnesium chloride is formed. The formation pentachlorophenylmagnesium chloride is explained on the basis of metal—hydrogen exchange reaction between 2, 3, 5, 6-tetrachlorophenylmagnesium chloride and the unreacted pentachlorobenzene.     

Spectrophotometric determination of trimethoprim by oxidation in drug formulations

A spectrophotometric determination of trimethoprim is described based on the reaction of its amine group with persulfate which acts as a strong oxidizing agent in alkaline media. The reaction produces a stable yellow colored compound after heating in a boiling water bath for 30 min. At λ_max 355 nm, Beer’s law is obeyed in the concentration range 10–60 μg ml^–1 with a molar absorptivity of 2.7 × 10³ l mol^–1cm^–1. The method is applied to formulations with sulfamethoxazole. Received: 30 July 1996 / Revised: 16 October 1996 / Accepted: 22 October 1996     

应用不同光谱技术,动物RBC,Hb及人皮肤表面血流氧化-还原状态检测

目的:检测与分析实验动物血液RBC(RBC·O2,RBC·CO2),Hb(HbO2,HbCO2)和人体皮肤表面流动血液氧化·还原状态的成像与未成像可见光谱领域OD值特征,并为该技术对白癜风病表皮黑色素颗粒检测中的应用尊定基础。方法:利用不同光谱技术和invitro和invivo检测手段,统计分析血液不同状态下波长与位置的OD值信息。结果:invitro检测:动物血液Hb·O2和RBC·O2两者在可见领域均有367,414(Soret带)nm与541,576(Q带)nm的吸收峰位;血液Hb·CO2和RBC·CO2均有432(Soret带)与和553(Q带)nm的波长吸收峰位;血液RBC状态和Hb溶血状态波长吸收峰位无改变,只是在氧化与还原状态下有完全独立的吸收峰位,血液RBC状态和Hb溶血状态波长吸光度OD值之间,有显著性差异(p<0·01)。浓度为1·5×107cell·mL-1的RBC·O2和Hb·O2在576nm的吸收峰位吸光度(y)与红细胞浓度(x)做成两条回归曲线:既,Hb·O2(b1)^y=0·05 0·983x;RBC·O2(b2)y^=0·127 1·934x,两者之间差异有显著性(p<0·01)。invivo检测:在人手背皮肤表面ImSpector图像中RBC·O2状态在540,576nm,RBC·CO2状态在555和755nm处有吸收峰。选择(a:指甲,b:指,c:手背)三个点位分别进行波长检测,每点(n=10)545nm吸收峰的平均OD值,依次为0·83±0·001,0·73±0·001和0·62±0·001,其三处测定点的OD值之间有显著性差异(p<0·01)。结论:invitro检测的RBC与Hb两者波长吸收峰位不变,但吸光度OD值不同,认为RBC状态测定结果更接近于活体组织血管内原始状态。invivo检测对人体无任何侵袭与损伤,灵敏度高,测试时间短,并且同时获得被测样品的波长与位置信息画面等优势,有望表皮中黑素等有色颗粒的直接检测。     

Amphitropic liquid crystals. Two lamellar phases in a surfactant containing thermotropic and lyotropic mesogenic groups

Abstract

We have studied the lyotropic liquid-crystalline behaviour of cationic surfactants containing a potentially thermotropic moiety, a terminal cyanobiphenyloxy group. Both mono-alkyl and mid-chain substituted dialkyl surfactants have been examined using optical microscopy and NMR spectroscopy. Incorporation of the cyanobiphenyloxy group destabilizes the hexagonal and bicontinuous cubic phases, with only an extensive lamellar region being observed. For the dialkyl surfactant there is a range of compositions where two lamellar phases co-exist, one water-rich and the second surfactant-rich.     

Non‐vacuum field desorption ion source implemented under super‐atmospheric pressure

Standard field desorption (FD) ionization is implemented under high vacuum condition. In this paper, non‐vacuum FD is performed under a super‐atmospheric pressure environment using untreated tungsten wires as FD emitter, and the ion source was coupled to a commercial linear ion trap mass spectrometer. The operating pressure of the ion source was 6 bars which was high enough to provide sufficient dielectric strength to the working gas so that the high voltage that was required for FD could be applied to the emitter without occurrence of electrical discharge. Non‐volatile sample deposited on the bare tungsten wire FD emitter was heated by flowing direct current through the emitter. Similar to vacuum FD, the formation of conical protrusion of the liquefied sample layer under the strong electric field was also observed. Using the present ion source, high pressure field‐desorption of polar neutral compounds, organic salts and ionic liquids is demonstrated. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis of Diaryl Ethers Through the Copper-Catalyzed Arylation of Phenols with Aryl Iodides Using KF/Al2O3

An efficient synthesis of diaryl ethers by the copper-catalyzed arylation of phenols with a variety of aryl iodide susing KF/Al₂O₃ as a suitable base and CuI and 1,3 diphenyl-1,3 propandione as the catalyst is described.     

Enhanced Optical Properties of FeS2 Using Ni@Cu Doping and Characterization of the Structural and Chemical Compositions for Solar Cell Applications

Crystallography Reports - Transition metals doped FeS2 thin films are promising materials for optoelectronics, energy saving and storage applications. This is a first time report on the...