摘要:

AbstractSwitching devices that operate on the molecular level lie at the heart of nanomachinery. The energies involved range from scores of kcal/mol during cleavage or formation of covalent bonds to a few kcal/mol when the signals are changes in conformation. Here we examine three systems that use light, metal/ligand binding, and acid/base chemistry as switching devices to transfer molecules in and out of the confined environments of encapsulation complexes or cavitands. The events are reversible and the original states can be recovered by treatment with brief heating, conventional chelating agents, or changes in protonation states, respectively. The control over these spaces augurs well for applications in drug delivery and sensors for small molecules.

ISSN:0009-4536    

DOI:10.1002/jccs.201000083

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractA simple, efficient, and environmentally friendly procedure for the amination of organic halides catalyzed by CuSO4·5H2O in PEG1000‐DIL/methylcyclohexane temperature‐dependent biphasic system is described. The product can be easily isolated by a simple decantation, and the catalytic system can be recycled and reused without loss of catalytic acti

ISSN:0009-4536    

DOI:10.1002/jccs.201000084

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractA highly selective and efficient method for the synthesis of novel polyamine fluorescence sensors is being offered. Remarkable increase of yields was observed, due to using potassium carbonate as proton trapper. The reaction is fast and easy‐to‐run in favorable conditions which accompanying by fewer side effe

ISSN:0009-4536    

DOI:10.1002/jccs.201000085

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractThree‐component one‐pot synthesis of some novel 6‐bromoquinolines5a‐5hinvolving the treatment of 2‐aminobenzophenone, α‐methylene carbonyl compounds, and tetrabutyl‐ammonium tribromide was achieved, and this reaction was extended to the preparation of 6‐iodoquinolines6a‐6eby a three‐component reaction 2‐aminobenzophenone, α‐methylene carbonyl compounds, and benzyltrimethylammonium dichloroiodate

ISSN:0009-4536    

DOI:10.1002/jccs.201000086

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractA new and novel UV spectrophotometric method has been developed for the determination Cu(II) in synthetic mixture and water samples. The method is based on complex formation of Cu(II) with cefixime immediately in 1,4‐dioxan‐distilled water medium at room temperature. The complex showed maximum absorption wavelength at 336 nm. Beer's law is obeyed in the concentration range of 1.015‐8.122 μg mL−1(Linear regression: A = 1.59 × 10−3+ 1.305 × 10−1C) with apparent molar absorptivity (8.29 × 103L mol−1cm−1) and Sandell's sensitivity (0.008 μg/cm2/0.001 absorbance unit). The limits of detection and quantitation for the developed method are 3.19 × 10−2and 9.65 × 10−2μg mL−1, respectively. Interferences due to Mn(II), Ca(II), Mg(II), Cd(II), Al(III), Pb(II), Zn(II), Fe(II), Fe(III), Ni(II), Cr(III), Hg(II) and As(III) was investigated. Nine cations do not interfere in the determination of Cu(II). Proposed method was successfully applied to the determination of Cu(II) in synthetic mixtur

ISSN:0009-4536    

DOI:10.1002/jccs.201000087

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractA methacrylate‐based monolith was initially prepared in fused‐silica capillary, using microwave irradiation. The electrophoretic and chromatographic behaviors of the prepared capillary monolithic columns were comparatively evaluated in the modes of pressure‐assisted capillary electrochromatography, capillary electrochromatography and low pressure‐assisted liquid chromatography. Baseline separation of the model analytes was, respectively, achieved with the lowest theoretical heights up to 17.0 μm, 28.4 μm and 16.3 μm for thiourea. A scanning electron micrograph of a cross‐section of the capillary column showed that the monolith was formed in the center of the capillary and adhered to the colum

ISSN:0009-4536    

DOI:10.1002/jccs.201000088

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractArtificial neural network has been demonstrated the capability of identifying the chemical composition from various analytical methods. This study tested the feasibility of using a single network to calculate data obtained from polarography, linear scanning voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). Computer generated data were used for network learning and testing. The network property of a single layer network was calculated at various learning cycles, learning rates, and β values of the neuron activation function. This study also evaluated two‐layer, three‐layer, and four‐layer networks. Test results conclude that a single artificial neural network could analyze various analytical data by using corresponding weight matrices. To produce accurate results, the network requires high training cycle, small β value of sigmoid function, and small learning rate. Network accuracy increase as the number of neuron increased to certain extents. Network structure plays minimum effects on the accuracy of network for a given number of

ISSN:0009-4536    

DOI:10.1002/jccs.201000089

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractA new and simple method for determination of calcium and magnesium in human plasma and hair samples was investigated by using potentiometric stripping analysis. The replacement reactions between Ca2+ and Zn‐EGTA (Ethylene glycol‐bis‐(2‐aminoethyl)tetraacetic acid) complex and between Mg2+ and Zn‐EDTA (Ethylenediamine tetraacetic acid disodium salt) complex were utilized. The determinations were carried out in NH4Cl‐NH3buffer solutions of pH 9.54 for calcium and of pH 10.18 for magnesium, respectively. Potential and time data were digitally converted into dtdE−1, andEwas plotted vs. dtdE−1. Quantitative analysis was carried out by the method of standard additions. Linearity for determination of magnesium was found to be in the range of 6∼120 μg L−1with a correlation coefficient of 0.997 (n= 6); and for determination of calcium in the range of 10∼250 μg L−1with a correlation coefficient of 0.995 (n= 6). The detection limit of 4 μ gL−1was found for both magnesium and calcium determination. This proposed method has been used for determining calcium and magnesium in biological samples with good recoveries and well accord with the results of Inductively Coupled Plasma‐Atomic E

ISSN:0009-4536    

DOI:10.1002/jccs.201000090

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractThe preparation of 4,4′‐dibromobenzilmonoxime (BBOH) (1) and its complexes Na[M(BBO)3] (where M = Mn(II) (2), Co(II) (3), Cu(II) (4)) are described. The ligand (BBOH) was prepared in MeOH from the reaction of 4,4′‐dibromobenzil with hydroxylamine hydrochloride in the presence of sodium acetate.Reaction of sodium salt of 4,4′‐dibromobenzilmonoxime (BBONa) in MeOH with Mn(CH3COO)2.4H2O, Co(CH3COO)2.4H2O and Cu(CH3COO)2.H2O yielded Na[Mn(BBO)3] (2), Na[Co(BBO)3] (3), and Na[Cu(BBO)3] (4) precipitates respectively.The analysis of IR,1H‐ and13C‐NMR spectral data of Mn(II), Co(II) and Cu(II) complexes suggest that 4,4′‐dibromobenzilmonoximate is bonded to metal(II) ions through the oxygen atom of the carbonyl, and the nitrogen atom of the oxime groups. The electronic spectral data of the complexes in DMSO are in good agreement with the octahedral coordination of M(II) ions.The splitting energy and Racah parameter were calculated to be 17136 cm−1and 816 cm−1for Na[Mn(BBO)3] (2), 15200 cm−1and 733 cm−1for Na[

ISSN:0009-4536    

DOI:10.1002/jccs.201000091

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY

摘要:

AbstractDi‐ and triorganotin(IV) complexes with the general formulae RnSnL4‐n, where R = Me,n‐Bu, Ph and L = 2‐[(2′‐methylphenylamido)]benzoic acid have been synthesized by the reaction of triethylammonium salt of 2‐[(2′‐methylphenylamido)]benzoic acid with di‐ and triorganotin chloride in dry toluene. All the synthesized complexes were characterized by elemental analysis, FT‐IR, multinuclear (1H,13C,119Sn) NMR, mass spectrometry and semi‐empirical study to assess the binding mode of 2‐[(2′‐methylphenylamido)]benzoic acid. The diorganotin(IV) derivatives are assessed to adopt distorted octahedral and triorganotin(IV) have linear polymeric trigonal bipyramidal structures in which 2‐[(2′‐methylphenylamido)]benzoic acid is a monoanionic bidentate, coordinating through C(O)O group. This coordination behaviour is also confirmed by semi‐empirical study. The isotopic effect of tin was studied by comparison of experimental data with the simulated isotopic pattern using the Chemtool software package. The insecticidal, antileshmanial, antibacterial, antifungal and cytotoxicity of the synthesized compounds are also reported. Some complexes exhibit good activities comparable to that of standard drugs. Furthermore, triorganotin(IV) derivatives exhibit significantly better activities than the diorganotin(IV) derivatives an

ISSN:0009-4536    

DOI:10.1002/jccs.201000092

出版商:WILEY‐VCH Verlag    

年代:2010

数据来源: WILEY