摘要:

AbstractMicrocalorimetric bioassay for acute cellular toxicity is based on metabolic heat production from cultured cells. The biological response to toxicants is the inhibition of the heat production rate in cells, and toxicity is expressed as the concentration of toxicant that is 50% effective in this inhibition (IC50). In mis paper, the effect of Na2SeO3onBacillus subtilisgrowth was investigated at 37 °C by microcalorimetry. The relationship between growth rate constants (k) and concentration of Na2SeO3(c) shows a logarithmic normal distribution, andlC50is 20.3 μg/mL. All these thermokinetic information is readily obtained by an LKB 2277–204 heat conduction microcalorimeter. Microcalorimetry is a quantitative, inexpensive, and versatile method for toxicology resea

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200202

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractPerylene nanoparticles with different sizes were prepared by reprecipitation method. It is found that the nanoparticles show size‐dependent optical property. Electron diffraction patterns indicate that all the nanoparticles of different sizes are in crystalline state. The rapid growth of the nanoparticles during the aging process could be slowed down effectively by the addition of cationic or anionic surfactant

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200203

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractGold nanoparticles with size 3–10 nm (diameter) were prepared by the reduction of HAuCl4in a CTAB/octane + 1‐butanol/H2O reverse micelle system using NaBH4as the reducing agent. The as formed gold nanoparticle colloid was characterized by UV/vis absorption spectrum and transmission electron microscopy(TEM). Various capping ligands, such as alkylthiols with different chain length and shape, trioctylphosphine (TOP), and pyridine are used to passivate the gold nanoparticles for the purpose of self‐organization into superstructures. It is shown that the ligands have a great influence on the self‐organization of gold nanoparticles into superlattices, and dodecanethiol C12H25SH is confirmed to be the best ligand for the self‐organization. Self‐organization of C12H25SH‐capped gold nanoparticles into 1D, 2D and 3D superlattices has been observed on the carbon‐coated copper grid by TEM without using any selective precip

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200204

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractA novel crown ether, 2,3‐naphtho‐10‐aza‐15‐crown‐5 (NAC) was synthesized. This compound does not show strong fluorescence and phosphorescence due to photoinduced intramolecular electron transfer from the nitrogen lone pair of electrons to the singlet excited state of the naphthalene chromophore. Complexation with heavy‐metal ions results in the quenching of the fluorescence and enhancement of the phosphorescence significantly. These observations were interpreted in terms of the binding interactions, between the nitrogen lone pair electrons and the metal cation, which prevent photoinduced intramolecular electron transfer, and the heavy‐atom effects which induce quenching of the fluorescence and enhancement of the phosphorescence. These azacrown and heavy‐metal‐based systems could be useful as potential chemical sensors and molecul

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200205

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractA novel one‐dimensional coordination polymer,Catena‐poly [bis(4‐cyano‐pyridyl) copper(II)‐di‐thiocyanate],1∞[CuII‐(cypy)2(μN.S‐SCN)2] (cypy = 4‐cyano‐pyridyl), was synthesized in a solution reaction of Cu(NO3)2·3H2O, 4‐cyano‐pyridine and KSCN in mole ratio of 1:2:2 at room temperature. Its crystal structure was determined by single‐crystal X‐ray diffraction. The crystal belongs to monoclinic crystal system, space groupP21/c with cell parametersa= 1.0719(2),b =1.8441(4),c=0.9144(2) nm, β = 110.49(3)° andZ= 4. A full‐matrix least‐squares refinement gaveR1= 0. 0393 andwR2= 0.0916 for 1554 reflections having1>2σ(I). The crystal is therm

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200206

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractThe ferrocene‐lipid film electrode was successfully prepared by means of casting the solution of ferrocene and lipid in chloroform onto a glassy carbon (GC) electrode surface. Ferrocene saved in the biological membrane gave a couple of quasi‐reversible peaks of cyclic voltammogram. The electrode displays a preferential electrocatalytic oxidation of dopamine (DA). The effect of electrocatalytic oxidation of DA depends on the solution pH and the negative charge lipid is in favor of catalytic oxidation of DA. The characteristic was employed for separating the electrochemical responses of DA and ascorbic acid (AA). The electrode was assessed for the voltammetric differentiation of DA and AA. The measurement of DA can be achieved with differential pulse voltammetry in the presence of high concentration of AA. The catalytic peak current was proportional to the concentration of DA in the range of 1 × 10−4–3 ×

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200207

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractA surface‐renewable tris(1, 10‐phenanthroline‐5, 6‐dione) iron (D) hexafluorophosphate (FePD) modified carbon ceramic electrode was constructed by dispersing FePD and graphite powder in methyltrimethoxysilane (MTMOS) based gels. The FePD‐modified electrode presented pH‐dependent voltammetric behavior, and its peak currents were diffusion‐controlled in 0.1 mol/L Na2SO4+ H2SO4solution (pH = 0.4). In the presence of iodate, dear electrocatalytic reduction waves were observed and thus the chemically modified electrode was used as an amperometric sensor for iodate in common salt. The linear range, sensitivity, detection limit and response time of the iodate sensor were 5 × 10−6–1 × 10−2mol/L, 7.448 μA·L/ mmol, 1.2 × 10−6mol/L and 5 s, respectively. A distinct advantage of this sensor is its good reproducibility of surface‐renewal by

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200208

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractEffects of self‐coiling of organic molecules on intramolecular exciplex formation of compound I, in which the carbazole chromophore and terephthalic acid methylester acceptor group are linked by one (CH2)10chain, and the decrease of the fluorescence intensities of compounds II, III, and IV, in which the carbazole chromophore and 3,5‐dinitrobenzoate are connected by one aliphatic chain of (CH2)10(II), (CH2)12(III), or (CH2)4(IV), have been studied in the dioxane(DX)‐H2O binary system. The results show that self‐coiling of organic molecules in DX‐H2O facilitates intramolecular exciplex formation of I and induces the decrease of fluorescence intensities of II, because of the proximity effect brought about by self‐coiling of organic molecules under hydrophobic‐lipophilic interaction (HLI) between the excited carbazole chromophore and the acceptor. Since the similar effects are observed even when the concentrations of the probes are less than their CAgCs (critical aggregate concentrations) in the DX‐H2O mixture with the same ϕ values, formation of the intermolecular exciplex has been excluded. The effects are found to be strongly depended on ϕ values, indicating that they are mainly driven by HLI. The properties of the acceptors can also affect the intramolecular exciplex formation. With terephthalic add methylester moiety as the acceptor, the carbazole chromophore exhibits the fluorescence spectra of the exciplex, while with 3,5‐dinitrobenzoate moiety as the acceptor, only the fluorescence spectra of excited carbazolyl chrom

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200209

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractTreatment of 4‐amino‐3‐(1‐aryl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐5‐mercapto‐1, 2,4‐triazoles/2‐amino‐5‐(1‐aryl‐5‐methyl‐1,2, 3‐triazol‐4‐yl)‐1,3,4‐thiadiazoles with benzaldehyde, acetone and ω‐bromoacetophenone was tested and compared. The title compounds Schiff bases, amides, imidazolo[2, 1‐b]‐1,3,4‐thiadiazoles and 7H‐s‐triazolo [3, 4‐b]‐1, 3, 4‐thiadiazines have been confirmed by elemental analyses,1H NMR, IR and MS spectra. All the compounds have also been screened for

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200210

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY

摘要:

AbstractYtterbium metal reacts with iodine to generate ytterbium diiodide directly, which can react with diselenides to form ytterbium selenolates (RSeYbI2). These species reacted smoothly with allyl bromide to give allyselenides in moderate to good yields under neutral conditions.

ISSN:1001-604X    

DOI:10.1002/cjoc.20020200211

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2002

数据来源: WILEY