摘要:

AbstractThe first metal‐carbon bond β‐form paddlewheel complexes containing a Pd24+core, [Pd(η2‐dithio)]2(μ‐dppa)( μ‐SCNMe2) (dithio = S2P(OEt)2,2; S2COEt,3; S2CNC4H8,4), were prepared by the reactions of the α‐form paddlewheel‐type Pd2+4dipalladium complex [Pd2(μ‐Hdppa)2(μ‐SCNMe2)2][Cl]2,1with various dithio‐ligands, [NH4][S2P(OEt)2], [K][S2COEt] and [NH4][S2CNC4H8], in methanol at ambient temperature (Hdppa = bis(diphenylphosphino)amine). Electronic spectra and two X‐ray structures of the Pd2+4

ISSN:0009-4536    

DOI:10.1002/jccs.200700001

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractA series of novel 2,5‐disubstituted 1,3,4‐oxadiazole derivatives were synthesized and tested for theirin vitroantimycobacterial activity. Some compounds showed interesting activity against a strain ofMycobacterium tuberculosisH37Rv. The result of the antimycobacterial activity tests revealed that 2‐(2‐naphthyloxymethyl)‐5‐phenoxymethyl‐1,3,4‐oxadiazole (IVd) exhibited>90% inhibiti

ISSN:0009-4536    

DOI:10.1002/jccs.200700002

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractViscosities of noble gases have been calculated over a wide temperature‐pressure range. Simple and accurate Tang‐Toennies potential of the noble gases are used in the Chapman‐Enskog calculation of the zero density viscosity and in the Rainwater‐Friend theory to determine the initial density dependence of the viscosity. At densities beyond the range of the theory (up to 46 mol.dm−3), a variant of the residual viscosity is developed. A correlation function for the calculation of viscosity over the whole range of density is presented. A comparison of the calculated and experimental values of the viscosity yields an average absolute deviatio

ISSN:0009-4536    

DOI:10.1002/jccs.200700003

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractSimultaneous kinetic‐spectrophotometric determination of a ternary mixture of hydrazine (HZ) and its derivatives by principal component regression (PCR) and partial least squares (PLS) calibration is described. The methods were based on the difference observed in the reduction rate of iron(III) with HZ, thiosemicarbazide (TSCZ) and phenylhydrazine (PHZ) in the presence of 2,2′‐bipyridine (Bpy). The colored complex of [Fe(Bpy)3]2+was formed in sodium dodecyl sulfate (SDS) as micellar media, and then monitored at 520 nm. The results showed that simultaneous determination of HZ, TSCZ and PHZ could be performed in their concentration ranges of 1.0–70.0, 0.2–6.0 and 0.1–10.0 μg mL−1, respectively. The root mean squares errors of prediction (RMSEP) of HZ, TSCZ and PHZ were 0.719, 0.164 and 0.105 (for PLS) 0.788, 0.166 and 0.993 (for PCR), respectively. Both methods (PCR and PLS) were validated using a set of synthetic sample mixtures and then applied for simultaneous determination of HZ, TSCZ and PHZ in

ISSN:0009-4536    

DOI:10.1002/jccs.200700004

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractA new series of vanadium(III) complexes with oxygen donor ligands have been synthesized and characterized on the basis of elemental analysis, conductance, infra‐red spectroscopy, electronic spectral data and mass spectrometry. Thermal stabilities of the complexes and their kinetics were studied through thermogravimetric analysis. Estimation of vanadium in the complexes is carried out by ICP‐AES. Biological activities of the complexes2–5,7and8have also been tested against various bacteria and

ISSN:0009-4536    

DOI:10.1002/jccs.200700005

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractThe liquid precipitation method using zinc acetate dihydrate was applied for the synthesis of uniform and spherical ZnO nanoparticles. The ultrafine zinc oxid was prepared in a water‐ethanol mixture solution. The solution containing zinc cation was soluble in water. The surface‐active agent triethanolamine (TEA) was soluble in ethanol. Then alkali precipitated by adding n‐propylamine. The spherical zinc oxide particle morphology was found to be highly dependent on the zinc salt concentration, ethanol‐water ratio, and the surface‐active agent additive. The process can produce white ZnO powder of 50–90 nm in size. The morphology of zinc oxide showed a powder shape by transmission electron microscopy (TEM), the crystallization phase structure of zinc oxide by X‐ray diffraction (XRD), and the zinc oxide remaining by using an organic analysis by infrared spec

ISSN:0009-4536    

DOI:10.1002/jccs.200700006

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractWall thickness of siliceous MCM‐41 could be controlled systematically up to 36.1 Å. A reasonable model explaining formation of thicker MCM‐41 walls, not enlarging pore channel is proposed on the basis of TGA and13C MAS NMR data of samples. Thermal restructuring process under mild basic condition favors the silica redeposition on silica wall and building up thicker wall. Most mesostructure of calcined MCM‐41 with thicker wall was retained even after hydrothermal treatment in boiling water for 14 days. To our best knowledge, the excellent hydrothermal stability of the MCM‐41 silica reported herein has not been described before and facilitates practical applications of mesoporous molecular sieves i

ISSN:0009-4536    

DOI:10.1002/jccs.200700007

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractA new tocopherol derivative, 7a‐methoxy‐α‐tocopherol (1), and a new taraxastane triterpene, taraxast‐1,20(30)‐dien‐3‐one (5), together with four known compounds, β‐tocopherol (2), α‐tocopherol (3), α‐tocospiro B (4) and taraxasterone (6) were isolated from the whole plant ofSida acuta.Their structures were elucidated by spectral analysis including MS, 1D and 2D‐NMR spectroscopy. Among those compounds, compounds1,2, and3showed significant antioxidant effect (EC50= 86.9, 68.2, and 70.9 μM, respectively) in the DPPH radicals

ISSN:0009-4536    

DOI:10.1002/jccs.200700008

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractA kinetic method for the determination of micro quantities of amino acid arginine (Arg) is described in this paper. The catalytic activity of cobalt in the reaction of oxidation of purpurin (1,2,4‐trihydroxy‐antraquinone, PP) by hydrogen peroxide in alkaline buffer solution decreases in the presence of micro quantities of arginine, because of the formation of the complex. Operating conditions for the successful determination of arginine were optimized. The optimized conditions yielded a theoretical detection limit of 1.45 μg mL−1. Kinetic equations are proposed for the investigated process. The interference effects of certain foreign ions and amino acids upon the reaction rate were studied and removed in order to assess the selectivity of the method. The developed procedure was successfully applied to the determination of arginine in various pharmaceutical samples. The typical feature of this procedure is that determination can be carried out at room temperature and in a short analysis time. The newly developed method is simple, inexpensive and efficient for use in the analysis of a large number of s

ISSN:0009-4536    

DOI:10.1002/jccs.200700009

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractA novel PVC‐based membrane sensor based on 2,6‐(p‐N,N‐dimethylaminophenyl)‐4‐phenylthiopyrylium perchlorate (DAPP) is described. The electrode exhibits a sub‐Nernstian response to 1‐(beta‐hydroxyethyl)‐2‐methyl‐5‐nitroimidazole (metronidazol) over a relatively wide concentration range (1.0 × 10−1to 1.0 × 10−5M) with a detection limit of 8.0 × 10−6M. The best performance was obtained with the membrane containing 30% poly (vinyl chloride), 50% dibutyl phthalate, 7% DAPP and 13% oleic acid. It has a fast response time (<30 s) and can be used for at least four weeks without any major deviation. The proposed sensor revealed very good selectivity for metronidazole over a wide variety of common cations, anions and amino acids and could be used in the pH range of 6.0–7.5. It was successfully used for direct determination of metronidazole in an oral synthetic antiprotozoal as an antibacterial agent, in metronidazole tablets, and metronidazo

ISSN:0009-4536    

DOI:10.1002/jccs.200700010

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY