Electrochemical behaviour of triphenylgermanium bromide

The electrochemical behaviour of triphenylgermanium bromide has been thoroughly investigated using various electrochemical techniques including polarography, cyclic voltammetry and controlled potential coulometry. It has been found that in non-aqueous solvents triphenylgermanium bromide gives only one small drawn-out wave, while in aqueous-organic media two reduction waves are observed. The first wave has been ascribed to adsorption of the products of the reduction step II. The triphenylgermanium free radicals have been postulated to combine rapidly with protons in acidic media or to abstract hydrogen from water in alkaline media. The protonated species has been found to be reduced at potentials at which normal reduction of triphenylgermanium bromide takes place giving rise to a superimposed catalytic proton-discharge wave. A mechanism of reduction of triphneylgermanium bromide at the DME has been postulated and analytical methods for the determination of triphenylgermanium compounds at the formulation and trace analysis levels have been developed.     

吸附物准可逆表面反应示波极谱峰电流及其验证

本文讨论了吸附物在滴汞电极上的准可逆表面反应示波极谱峰电流表达式,并进行了实验验证。     

TETRABUTYLAMMONIUM－TETRACYANOQUINODIMETHANE AS ELECTRON－TRANSFER MEDIATOR IN AMPEROMETRIC GLUCOSE SENSOR

ＴＥＴＲＡＢＵＴＹＬＡＭＭＯＮＩＵＭ－ＴＥＴＲＡＣＹＡＮＯＱＵＩＮＯＤＩＭＥＴＨＡＮＥＡＳＥＬＥＣＴＲＯＮ－ＴＲＡＮＳＦＥＲＭＥＤＩＡＴＯＲＩＮＡＭＰＥＲＯＭＥＴＲＩＣＧＬＵＣＯＳＥＳＥＮＳＯＲ￥ＣｈａｎｇＱｉｎｇＳＵＮ；ＷｅｎＢｅＳＯＮＧ；ＤｕｏＺ...     

Nuclear reactivity indices in the context of spin polarized density functional theory

In this work, the nuclear reactivity indices of density functional theory have been generalized to the spin polarized case and their relationship to electron spin polarized indices has been established. In particular, the spin polarized version of the nuclear Fukui function has been proposed and a finite difference approximation has been used to evaluate it. Applications to a series of triatomic molecules demonstrate the ability of the new functions to predict the geometrical changes due to a change in the spin multiplicity. The main equations in the different ensembles have also been presented.     

A versatile ternary ion pair complex of 2′-amino-1,1′-binaphthalen-2-ol for sensing enantiomers and assignment of absolute configuration

2′-Amino-1,1′-binaphthalen-2-ol (NOBIN) serves as a versatile chiral solvating agent (CSA) in the presence of trifluoromethanesulfonic acid (TFMS). The formation of a ternary complex has been established by NMR, UV–Vis, fluorescence and IR studies. The mechanism of interactions among the three components in the ternary complex has been proposed and the ternary complex structures of different diastereomers have been established by DFT based theoretical calculations. The present protocol has its ubiquity not only in the analysis of the enantiomeric composition of molecules possessing diverse functionalities, but also in determining the stereospecific assignment of hydroxy acids.     

Polarographic study of mixed ligand complex stability constants and kinetic parameters of reduction of zinc(II)-tartrate—Thiocyanate system

The Zn-tartrate-thiocyanate system has been investigated polarographically and the composition and stability constants of mixed complexes formed have been determined.     

3,5—二羟基甲苯比色法测定棉纤维表面糖的方法研究

本文研究了在非离子表面活性剂存在下,糖在强酸介质中转化成糠醛类衍生物同3.5-二羟基甲苯发生显色反应的条件。在硫酸介质中,糠醛与3,5-二羟基甲苯形成化合物的最大吸收波长为λ_(max)=425nm,线性范围0.04～0.20mg/ml,用于测定棉纤维表面的糖,方法的相对标准偏差为1.3％,回收率92％～105％。     

Molecular Mechanics Study on Asymmetry Catalysis

Theasymmetrycatalysisisanimportantchemicalreactionwidelyusedinbiology,pharmacyalldagriculture.Itispreferredtoenantioselectivehydrogenationofmethylpyruvate(MP)oversuppoFtedplatiniumnanoclusters.Cinchonidine(CD)isamodifier,aco-catalysttothereaction.Withoutthemodifier,therewouldbenoenantioselectivitytothehydrogenationofpyruvate.Inordertoobtainbetterunderstandingofthemechanismofthereaction,especiallytheroleofthemoditler,thepresentstudybymolecularmodelinghasbeenperformedandtheresultsarereportedhe…     

二茂铁-AQ修饰碳纤维微葡萄糖传感器的研究

本文用二茂铁、AQ成功地制备了微葡萄糖传感器。Eastman-AQ(AQ-55D,AQ29D)是一种新型的聚合物(磺酸酯)阳离于交换剂,涂于电极表面上,形成的膜除具有强的附着力外,同时还具有预富集、离子交换及防污性能。制得的电极具有制作方法简单、快速、重现性好,抗干扰能力强等特点。检测上限15.0 mmol/L,响应时间小于6s。由于AQ强的附着力,二茂铁及酶的流失较小。电极的稳定性有所提高。     

化学键理论对研究高T_C超导材料的作用

本文从化学键的观点出发综述了近年来高温超导体的合成。结构及性能关系,特别强调了化学在研究超导材料中的作用。     

Synthetic Studies of an Analogue of HIV-1 Protease Inhibitors of Didemnaketals:Construction of the C1-C8 Intermediate

ThedidenlnaketalsAandBhaveprovedtobesignificantinhibitorstoHIV-Iprotease'.UPtotilepresent.however,nosuccessfulsynthesishasbeenreported.Inconnectiollx'l,lthOLlrs}'ntheticstudiesoftheiranalogLles,wehavereportedasuccesslillsynthesisofthesimilarilltermediateof32.Hereinwewouldpresentanefficientprocedureforthediastereoselectivesynthesisofanotherintermediate4.Basedoiltileretrosyntheticanalysis,theintermediate4couldbesynthesizedfromllaturalI.-(-)-nlelltllollebecauseofthevaltlablechiralCSmethyl.…     

Monitoring of aromatic amines by HPLC with electrochemical detection: comparison of methods for destruction of carcinogenic aromatic amines in laboratory wastes

A new chemical method for destruction of carcinogenic aromatic amines in laboratory wastes has been developed. The method is based on enzymatic oxidation of the amines in solution (with hydrogen peroxide and horseradish peroxidase), followed by oxidation of the solid residues with permanganate in sulphuric acid medium. To monitor the efficiency of destruction, a reversed-phase HPLC system has been developed, with voltammetric detection with a carbon-fibre detector, which is substantially more sensitive (detection limits from a few ng down to a few pg of amine) than the commonly used ultraviolet photometric detection. It has been demonstrated that the proposed method of destruction is highly efficient (99.8% destruction).     

对微量元素与恶性肿瘤关系的新认识

微量元素与恶性肿瘤关系是当前十分引人注目的研究课题．MEDLINE数据库显示．近5年中硒、锌、铜与肿瘤关系的文章最多．微量元素与恶性肿瘤相关性有三种可能,即微量元素的丰缺是恶性肿瘤的结果.是肿瘤发生的条件因素或病因．微量元素之间的关系相当复杂．既拮抗。又协同，微量元素的研究刚起步．取样和检测方法等均需标准化．其与恶性肿瘤的发生和发展的机理更需积极研究.     

Stereoselective Michael-alkylation and Michael-oxidation reactions of chiral 1,3-dioxolanones

A highly diastereoselective Michael-alkylation/oxidation methodology has been developed for the synthesis of optically active α-hydroxy-1,5-diester subunits. Inverse stereochemistry at the C_2′ position could be achieved by using a Michael acceptor equipped with a suitable group followed by a highly stereoselective protonation. This methodology has been applied to the enantioselective synthesis of the upper fragment of (+)-retusine.     

吸附树脂和络合树脂联合处理对硝基苯乙酮生产废水的研究

本文采用南京大学研制的AM－1型吸附树脂和ND－900型络合树脂联合处理对硝基苯乙酮生产废水，系统地研究了流速、温度、废水的pH值等因素对树脂吸附性能的影响，以及以NaOH为脱附剂，其流速、浓度、温度等对树脂脱附性能的影响。当废水的处理量为30BV时，其CODCr总去队达93％，表明树脂吸附性能良好。     

Kinetics and mechanism of the oxidation of some aliphatic ketones by n-bromoacetamide in acidic media

Kinetics of the oxidation of methyl ethyl ketone (MEK) and diethyl ketone (DEK) by N-bromoacetamide (NBA) have been studied in perchloric acid media in the presence of mercuric acetate. A zero order dependence to NBA and a first-order dependence to both ketones and H⁺ have been observed. Acetamide, mercuric acetate and sodium perchlorate additions have negligible effect while addition of acetic acid has a positive effect on the reaction rate. A solvent isotope effect (K₀D₂O/k₀H₂O = 2.–.4 and 2.2-2.5 for MEK and DEK, respectively) has been observed at 40°. Kinetic investigations have revealed that the order of reactivity is MEK > DEK. The rates were determined at four different temperatures and the activation parameters were evaluated. The main product of the oxidation is the corresponding 1,2-diketone. A suitable mechanism consistent with the above observations has been proposed.     

Etude Electrochimique d'Un Nouveau Neuroleptique: La Loxapine

Abstract

The electrochemical characteristics of loxapine have been determined using D.C., A.C. and D.P. polarography and cyclic voltamnetry. The reduction of the azomethin group is influenced by the vicinity of the protonable piperazin ring. Adsorption phenomena have been observed, especially in alkaline medium. The determination of loxapine can be easily carried out quantitatively in acidic medium, and an application of the method for the determination of loxapine in tablets has been realized. The simultaneous detection of loxapin and clothiapine, which are structurally related neuroleptics differing only by an oxygen or a sulfur atom in the central heterocycle is not possible; nevertheless, loxapine has been detected in neutral or alkaline medium in the presence of clozapine, which differs from the two precedents by the presence of a nitrogen as heteroatom.     

Ultra-sensitive hydrazine chemical sensor based on high-aspect-ratio ZnO nanowires

High-aspect-ratio ZnO nanowires based ultra-sensitive hydrazine amperometric sensor has been fabricated which showed a high and reproducible sensitivity of 12.76 μA cm⁻² nM⁻¹, detection limit, based on S/N ratio, 84.7 nM, response time less than 5 s, linear range from 500 to 1200 nM and correlation coefficient of R = 0.9989. This is the first report in which such a very high-sensitivity and low detection limit has been achieved for the hydrazine sensors by using ZnO nanostructures modified electrodes. Therefore, this work opens a way to utilize simply grown ZnO nanostructures as an efficient electron mediator to fabricate efficient hydrazine sensors.     

液固色谱中溶质保留规律的研究—多元流动相组成对保留值的影响

根据热力学原理和简单的吸附色谱分子模型。本文提出了一个新的液固色谱保留模型，并导出了相应的保留值基本方程，以三元溶剂系统作为展开剂，用薄层色谱实验数据验证了所得方程的正确性。结果显示，计算Ｒｆ值与实验Ｒｆ值完全一致。     

Mössbauer study of photolysis and γ-radiolysis of alkali bis(citrato) ferrates(III)

The photolysis of alkali bis(citrato) ferrates(III) M₃Fe(cit)₂·xH₂O (M = Li, Na, K, Cs, NH₄) in solid and solution phases and γ-radiolysis in solid state has been investigated using Mössbauer and IR spectroscopic techniques. The formation of iron(II) species as the ultimate product in all these complexes has been observed except the solid state photolysis of potassium bis(citrato) ferrate(III) in which the intermediate iron(II) moiety is oxidized to an octahedral iron(III) species.