Surface-renewable cobalt(II) hexacyanoferrate-modified graphite organosilicate electrode and its electrocatalytic oxidation of thiosulfate

Cobalt(II) hexacyanoferrate (CoHCF) was deposited on graphite powder by an in situ chemical deposition procedure and then dispersed into methyltrimethoxysilane-derived gels to prepare a surface-renewable CoHCF-modified electrode. The electrochemical behavior of the modified electrode in different supporting electrolyte solutions was characterized by cyclic voltammetry. In addition, square-wave voltammetry was employed to investigate the pNa-dependent electrochemical behavior of the electrode. The CoHCF-modified electrode showed a high electrocatalytic activity toward thiosulfate oxidation and could thus be used as an amperometric thiosulfate sensor.     

红外光谱法研究LB膜中的分子取向

The structure information of orientation and packing of molecular chains can be obtained from infrared transmission and reflection-absorbance (RA) spectra. In the present paper, on the basis of Umemura et al., their FORTRAN program of minicomputer was developed and can be run on 486 personal computer. By comparison of infrared transmission and RA intensities, surface enhancement factors and molecular orientation angle were calculated using the above program, and the influence of complex refractive index, angle of incidence, and thickness of LB film were discussed. These results are consistent with that of Umemura et al.     

最小一乘稳健多元分析校正

本文论述最小一乘求解的多元分析校正算法，探讨了最小一乘较常规最小二乘法及其他隐健算法的优点。用计算机数值模拟及实际多组分光谱体系对方法进行了检验，展示了最小一乘法在分析化学计量学中实际应用的可行性。     

Ziegler-Natta催化剂催化乙烯气相聚合

本文综述了乙烯气相聚合催化剂研究状况,列举了一些制备气相聚合催化剂有代表性的方法。同时对预聚合的作用及气相聚合与淤浆聚合表观动力学行为的不同性也作了简要介绍。     

过渡金属配合物阴离子嵌人聚吡咯膜电极的表征

采用电化学聚合方法在水溶液中制备出Fe(CN)_6~(4-)嵌入的聚吡咯膜修饰电极, 电极具有稳定的Fe(CN)_6~(4-)/Fe(CN)_6~(3-)电化学响应, 其氧化、还原电位与电解质溶液中H~+浓度有关。借助XPS、IR和ESR方法对聚合物膜结构进行表征, 探讨嵌入物种Fe(CN)_6~(n-)和聚吡咯之间的相互作用, 提出一种可能的轨道相互作用模式。     

2, 2＇─(1, 4─亚乙二氧基)—二苯甲酸与钴(Ⅱ)生成的两种配合物的结构研究

硝酸钴与２，２＇－（１，４－亚乙二氧基）－二苯甲酸（Ｈ２Ｌ，图１）作用分别得到红色配合物ＣｏＬ＇和蓝色配合物ＣｏＬ″。经元素分析、红外光谱、紫外可见光谱、热分析等方法进行了表征、ＣｏＬ＇配合物的分子式为［ＣｏＬ．Ｈ２Ｏ］．３Ｈ２Ｏ，近八面体构型，羧酸根以双齿形式与Ｃｏ（Ⅱ）螯合；ＣｏＬ″配合物分子式为［ＣｏＬ″］。Ｈ２Ｏ，近四面体构型，羧酸根以单齿形与Ｃｏ（Ⅱ）配位。     

Semipreparative separation and determination of eleutheroside E in Acanthopanax giraldii Harms by high-performance liquid chromatography

A method for the isolation, purification, and determination of eleutheroside E in Acanthopanax giraldii Harms, collected in the Sichuan province (China), is established. The water extraction of A. giraldii Harms is pre-isolated using macroporous adsorption resin (D-101) and a C18 solid-phase extraction cartridge, and the enriched extract is purified to give eleutheroside E (syringaresinol-di-O-beta-D-glucoside; liriodendrin) by semipreparative reversed-phase high-performance liquid chromatography. Structure identification is performed by a comparison of IR, 1H-NMR, 13C-NMR, and electrospray ionization-mass spectrometric data with the literature. The final purity of the compound is 97%. Quantitative determination of eleutheroside E in A. giraldii Harms is performed on a Zorbax SB C18 (150- x 4.6-mm i.d., 5 microm) column. The linear range of eleutheroside E is 4.85-194 mg/L (r = 0.9998), and the average recovery is 99.6-101%. The developed method is simple, reproducible, and easy to operate. It is useful for the evaluation of Acanthopanax giraldii Harms.     

A Rapid and Convenient Synthesis of Derivatives of Imidazoles under Microwave Irradiation

An efficient and a quick microwave‐assisted synthesis of benzimidazoles and trisubstituted imidazoles was developed. Three benzimidazoles were obtained as a result of the condensation of 1,2‐phenylenediamine with carboxylic acids and acetoacetic ester without catalyst. A series of trisubstituted imidazoles were synthesized by condensation of benzil, aromatic aldehyde and ammonium acetate in the presence of glacial acetic acid.     

Isolation and purification of inflacoumarin A and licochalcone A from licorice by high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) technique in semi-preparative scale has been applied to isolate and purify bioactive flavone compounds from the ethanol extract of Glycyrrhiza inflata Bat., a particular plant species of licorice. HSCCC separation was performed with a two-phase solvent system composed of n-hexane-chloroform-methanol-water (5:6:3:2, v/v) by eluting the lower mobile phase at a flow rate of 1.8 ml/min and a revolution speed of 800 rpm. Purification was performed with a two-phase solvent system composed of n-hexane-chloroform-methanol-water (1.5:6:3:2, v/v) by eluting the lower mobile phase at a flow-rate of 1.5 ml/min and a revolution speed of 800 rpm. Two major flavone peaks: inflacoumarin A and licochalcone A were collected and the respective yields of the peaks amount to 6 mg (8.6%, w/w) and 8 mg (11.4%, w/w) from 70 mg of the crude extract sample. The purities of inflacoumarin A and licochalcone A reached 99.6% and 99.1%, respectively, after a sequential purification run. The structures of inflacoumarin A and licochalcone A were positively confirmed by 1H NMR and 13C NMR, 1H-13C-COSY, UV, FT-IR and electron ionization MS analyses.     

Synthesis of 4H-Pyrrolo[2,1-C][1,4]benzothiazines and 3-(Methylthio)oxindoles

The Pummerer reaction was carried out with α-acylsulfides and phenyl iodosyl bis(trifluoroacetate) instead of α-acylsulfoxides to prepare 4H-pyrrolo[2,1-c][1,4]benzothiazines and 3-(methyIthio)oxindoles.