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121.
Renata Ga<parová Daniel Zbojek Margita Lácová Katarína Král'ová Anton Gatial Branislav Horváth Alžbeta Krutošíková 《Central European Journal of Chemistry》2005,3(4):622-646
The reactions of substituted furo[3,2-b]pyrrole-5-carboxhydrazides 1 with 5-arylfuran-2-carboxaldehydes 2, 4,5-disubstituted furan-2-carboxaldehydes 3 and thiophene-2-carboxaldehyde 4 has been studied. The advantage of microwave irradiation on some of these reactions was reflected in the reduced reaction
time and increased yields. Reactions of 1 with 4-substituted 1,3-oxazol-5(4H)-ones 11 led to diacylhydrazines 13 or to imidazole derivatives 14 depending on the temperature. 1,2,4-Triazole-3-thione 17 was synthesized by two-step reaction of 1 with phenylisothiocyanate and subsequent base-catalyzed cyclization of thiosemicarbazide 16. The effects of hydrazones 5–10 on inhibition of photosynthetic electron transport in spinach chloroplasts and chlorophyll content in the antialgal suspensions
of Chlorella vulgaris were investigated. 相似文献
122.
Mojumdar S. C. Kozánková J. Chocholoušek J. Majling J. Fábryová D. 《Journal of Thermal Analysis and Calorimetry》2004,78(1):73-82
Fluoroapatite containing glass-ceramics were prepared from Li2O-CaO-CaF2-P2O5-SiO2 system. The glass was melted at 1480°C for 1 h. The object of observation was the preparing crystal phase of fluoroapatite
in amorphous glass matrix. The morphology of lithium disilicate glass-ceramics was studied by SEM. The crystal growth and
thermal properties of fluoroapatite were studied by X-ray diffraction and DTA. The more the content of P2O5, the more the presence of fluoroapatite particles. SEM investigation clearly indicated the phase separation and formation
of a primary crystalline phase of fluoroapatite in the studied glass-ceramics. DTA curves of the fluoroapatite samples exhibit
exothermic effects in the temperature range 337-694°C depending on the composition of the materials. The position of exothermic peak for lithium disilicate on DTA curves moves with increasing specific surfacetowards lower temperatures which points on its preferential surface crystallization. As far as physical qualities are concerned,
mainly color and gloss, the best qualities of all observed materials belong to glass-ceramics with 10% P2O5.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
123.
124.
The kinetics of the thermal decomposition of solid complexes of the type Ni(NCS)2L2 (L=pyridine,β-picoline and quinoline), of pseudooctahedral configuration, were studied by using isothermal methods, on the basis of losses of weight, in the temperature range 90–191?. The most suitable reaction order for all the complexes under investigation was found to ben=2/3, i.e. the total decomposition rate is determined by the chemical process proper. The calculated values ofE a(in kcal · mole?1) decrease in the following order: Ni(NCS)2py2 (29.4)>Ni(NCS)2(β-pic)2 (27.6)>Ni(NCS)2Q2 (24.3). With increasing volume of the ligand L the reaction rate also increases, and this suggests that the reaction proceeds by dissociative activation. For all the investigated complexes it was found that δH>E A; this may be explained by a several-step mechanism and the complex Ni(NCS)2L is then considered an intermediate. 相似文献
125.
Marjan Kočevar Bojan Verček Branko Stanovnik Miha Tišler 《Monatshefte für Chemie / Chemical Monthly》1982,113(6-7):731-744
Pyrazine- and pyridinecarboxamidoximes with an amino, potentially tautomeric hydroxy or mercapto group inortho position could be transformed in the appropriate condensed azines. In this manner, representatives of pyrazolo(3,4-b)pyrazine, isoxazolo(4,5-b)pyrazine and isothiazolo(5,4-b)pyridine ring system were synthesized and some transformations investigated.Presented in part at the 8th International Congress of Heterocyclic Chemistry, Graz, 1981. 相似文献
126.
Zusammenfassung Eine Methode der Identifizierung von Alkyl- und Arylgruppen organischer Sulfide wurde ausgearbeitet, die die Spaltung dieser Stoffe mit Raney-Nickel zur gaschromatographischen Bestimmung der dabei entstandenen Kohlenwasserstoffe ausnützt.
Die Autoren danken den Kollegen Dr.M. Veea, Ing.J. Petránek und Ing.J. Gaspari für die Überlassung von Proben organischer Sulfide. 相似文献
Summary A method was developed for identifying alkyl- and aryl groups of organic sulfides. The method employs the cleavage of these materials with Raney nickel for the gas chromatographic determination of the resulting hydrocarbons.
Résumé On a mis au point une méthode d'identification des groupes alkylés et arylés des sulfures organiques exploitant la dissociation de ceux-ci par le nickel Raney pour le dosage par chromatographic en phase gazeuse des carbures d'hydrogène qui se forment.
Die Autoren danken den Kollegen Dr.M. Veea, Ing.J. Petránek und Ing.J. Gaspari für die Überlassung von Proben organischer Sulfide. 相似文献
127.
František Kvasnička Rudolf Ševčík Michal Voldřich Jana Krátká 《Central European Journal of Chemistry》2004,2(3):417-424
A simple and rapid capillary zone electrophoresis (CZE) method for the determination of aristolochic acid (AA) in dietary
supplements and selected herbs is described. A clear separation of AA from other sample constituents was achieved within 5
minutes without any sample clean up. A mixture of 20 mM-morpholinethanesulphonic acid+10 mM-BisTrisPropane+0.2% hydroxyethylcelullose
in 10% methanol serves as a background electrolyte. The linearity, accuracy, intra-assay and detection limit of the developed
method are 200–6000 ng/mL, 95–103%, 3.5%, and 50 ng/ml, respectively. Ease of use, sufficient sensitivity and low running
cost are the most important attributes of the CZE method. The proposed CZE method was compared with HPLC. 相似文献
128.
P. Kowalczyk S. Milošević G. Pichler 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1989,11(3):213-217
We have measured the effect of potassium vapour pressure within the heat-pipe oven on the shape of the 23 ∏ g ?13∑ u + fluorescence induced by collision energy transfer from theC 1∏ u state which was optically excited by the 457.9 nm argon-ion laser line. The estimated cross section of that process is 300 Å2. The simulation of the diffuse band shape indicates a non-thermalised vibrational distribution in the 23 ∏ g state. 相似文献
129.
The thermal properties of cyanatocopper complexes with pyridine, bipyridine and phenanthroline are described in this paper. It was found that the thermal stabilities of the complexes were found to increase in the order pybipy2(NCS)2 (L=pyridine and its methyl derivates) which are composed of the liberation of ligandsL and redox reactions of thiocyanate ligands with the central Cu(II) atom [1, 2]. The decomposition temperature of thiocyanate ligands depends on the properties of the ligandsL present in the coordination sphere. An analogous course of thermal decomposition was also observed for [Cu(bipy)2(NCX)](NCX) (X=S or Se) [3]. For the phenanthroline complexes [Cu(phen)2(NCX)2] (X=S or Se) the thermal stability was found to increase significantly (by about 140C) and the decomposition stoichiometry was also changed [3].The present paper contains the results of thermoanalytical studies on bipyridine and phenanthroline cyanatocopper complexes, and a comparison of the thermal properties of pyridine cyanato and isothiocyanatocopper complexes. 相似文献
130.
Photokilling Squamous Carcinoma Cells SCCVII with Ultrafine Particles of Selected Metal Oxides 总被引:1,自引:0,他引:1
Ivanković Siniša Gotić Marijan Jurin Mislav Musić Svetozar 《Journal of Sol-Gel Science and Technology》2003,27(2):225-233
The ability of ultrafine particles of TiO2, WO3 and iron-doped TiO2 to kill cancer cells in the presence of UV irradiation was investigated. The best photokilling effect on carcinoma cells SCVII cultured in vitro showed iron-doped TiO2 ultrafine particles synthesized by the sol-gel procedure with starting chemicals Ti(IV)-isopropoxide and anhydrous Fe(II)-acetate. It was found that a small particle size and high dispersity influenced citotoxicity and photocatalytic efficiency. The remarkable photokiling effect of highly iron-doped TiO2 ultrafine particles (the molar ratio Fe/Ti = 0.136) in the presence of UV irradiation was observed. The influence of ultrafine metal oxide particles on the inhibition of cancer cell proliferation was measured using a 3H-thymidine incorporation test. The possible mechanism involved in the photokilling of carcinoma cells with ultrafine particles of selected metal oxides was discussed. 相似文献