摘要:

AbstractLiving radical polymerization (LRP) of methyl acrylate (MA), acrylic acid (AA), and vinyl acetate (VAc) mediated by cobalt(II) porphyrin complexes ((TMP)CoII·, (TMPS)CoII·) are reported. The polymeric products with relatively low polydispersity and controlled number average molecular weight (Mn) based on one polymer chain per cobalt complex demonstrate the living characters of the polymerization process. The formation of block copolymers of poly(methyl acrylate)‐b‐poly(vinyl acetate) (PMA‐b‐PVAc) and poly(methyl acrylate)‐b‐poly(vinyl pyrrolidone) (PMA‐b‐PVP) demonstrate another important feature of LRP and extend the application of cobalt porphyrin mediated radical polymerization to a wider array of functionalized monomers. Kinetic studies using1H NMR to follow the formation of orGano‐cobalt complexes reveal that two mechanisms, reversible termination (RT) and degenerative transfer (DT), occur during the polymerization process. MA and VAc polymerization mediated by cobalt porphyrin complexes are used to illustrate the properties of these two LRP pathways and evaluate the kinetic and thermodynamic properties for several of th

ISSN:0009-4536    

DOI:10.1002/jccs.200900032

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractCarbon nanotubes (CNTs) possessing unique structure and properties are attractive building blocks for novel materials and devices of important practical interest. However, the insolubility or poor dispersibility of pristine CNTs in common solvents poses a serious obstacle to their further development. To effectively utilize CNTs as building blocks for nanotechnology, CNTs have been covalently and noncovalently functionalized in a number of ways to render them soluble in aqueous or organic solutions. Here, we review recent progress and advances that have been made on dispersion of carbon nanotubes in aqueous and organic media by non‐covalent functionalization with surfactants and polymer

ISSN:0009-4536    

DOI:10.1002/jccs.200900033

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractA simple and highly efficient green protocol for synthesis of bis(indolyl)methanes was carried out by the reaction of indole with aldehydes and ketones in the presence of FeCl3−based ionic liquid. These liquids serve as efficient media as well as Lewis acid catalyst

ISSN:0009-4536    

DOI:10.1002/jccs.200900034

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractSilica‐supported Preyssler nanoparticles (H14[NaP5W30O110])/SiO2are used as a new and recyclable catalyst for the preparation of 1,3‐diaryl‐5‐spirohexahydropyrimidines via a one‐pot condensation of anilines, formaldehyde, and cycl

ISSN:0009-4536    

DOI:10.1002/jccs.200900035

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractA wide range of aliphatic or aromatic sulfides are selectively oxidized to the corresponding sulfoxides using Al(NO3)3.9H2O, citric acid and a catalytic amount of KBr or NaBr in the presence of wet SiO2(50%w/w)in CH2Cl2under mild and heterogeneous conditions in good to high yields.

ISSN:0009-4536    

DOI:10.1002/jccs.200900036

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractA highly convenient method for the trimethylsilylation of alcohols and phenols via treatment by hexamethyldisilazane in the presence of 1,3–dichloro‐5,5–dimethylhydantoin (DCH) and/or trichloromelamine (TCM) as a catalyst has been developed. A wide variety of hydroxyl groups were selectively protected in CH2Cl2/CH3CN under mild condi

ISSN:0009-4536    

DOI:10.1002/jccs.200900037

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractSintering stainless steel powders was initially used to prepare the inlet frit in fused silica capillaries. The use of such inlet frits and outlet frits sintered by the stationary phase itself in the capillary to retain C18particles was demonstrated to withstand the long exposure, up to a high pressure of 60 MPa, for packing and the prepare column was stable and robust enough to do the continuous chromatographic operations. Characterization of the inlet and outlet frits by scanning electron micrography showed the fused metal particles formed a porous network in the capillary inlet and the homogenous separation beddings were obtained by slurry packing.

ISSN:0009-4536    

DOI:10.1002/jccs.200900038

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractFour novel stilbene derivatives containing 1,3,4‐oxadiazole unit have been synthesized in four steps with overall yields (27∼35%). The synthetic route involved one‐step installation of 2,5‐di‐p‐tolyl‐1,3,4‐oxadiazol via the direct coupling ofp‐toluic acid with hydrazine hydrate promoted byPPA, benzylic bromination, conventional phosphonate formation, and Wittig

ISSN:0009-4536    

DOI:10.1002/jccs.200900039

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractThe interaction of phenosafranine (PSF) with a glycosaminoglycan of heparin (Hep) in aqueous solution was characterized by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) in this paper and further used for Hep detection. In pH 1.5 Britton‐Robinson (B‐R) buffer solution PSF had a well‐defined voltammetric reductive peak at −0.256 V (vs SCE), and the electrochemical response was faded by the addition of Hep. Cyclic voltammetric experiments indicated that the electrochemical behaviors of free PSF didn't change no matter whether Hep was presented in PSF solution or not. Based on the decrease of the peak current, a second order derivative linear sweep voltammetry was used to establish a sensitive electroanalytical method for Hep. The peak current was proportional to the concentration of Hep in the range of 0.7∼20.0 mg L−1, demonstrating that this method was suitable for routine Hep detection. Under optimal conditions, the linear regression equation for the Hep determination was ΔIp”(nA) = 46.30 C (mg L−1) + 343.31 (n = 11, γ = 0.991) with a detection limit of 0.08 mg L−1(3σ). The established method was further successfully applied to heparin sodium injection samples determination. The interaction mechanism was discussed based on the electrostatic attraction of the negatively charged Hep with the positively charged PSF, and the stoichiometry of Hep‐PSF was calculated by t

ISSN:0009-4536    

DOI:10.1002/jccs.200900040

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY

摘要:

AbstractThis is the first time that the water‐dragging ability of aromatic compounds partitioning in octanolwater biphasic systems is experimentally estimated by a quantitative spectral deconvolution model. The water‐dragging amount, Δ f value, measured by the quantitative model is based on the integrations of peak area increments of component peaks deconvoluted from O‐H modes of water and octanol molecule, recorded by a Fourier‐transformed infrared spectrophotometer. The stoichiometry hydration capacity, Δ fw, is derived from the corresponding Δ f values. Without any tedious experimental procedure or complicated modeling calculation, the Δ fw value is able to give the required solute‐water hydration information. Such an advantage can't be provided by other techniques applied in the field of water‐dragging ability investigation. Six aromatic compounds were used for the method validation. The Δ fw data obtained by this model are generally consistent with literature‐known values. The efficiency of this quantitative spectral deconvolution model can solve the state of aggregations and the structure of hydrates existing in the organic phase. Moreover, this deconvolution model also has the ability to be extended further to investigate the environmental and biological problems related to the organic chemical portioning in the aqueous and

ISSN:0009-4536    

DOI:10.1002/jccs.200900041

出版商:WILEY‐VCH Verlag    

年代:2009

数据来源: WILEY