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71.
Kaoua R Bennamane N Bakhta S Benadji S Rabia C Nedjar-Kolli B 《Molecules (Basel, Switzerland)》2011,16(1):92-99
An efficient and improved procedure for the synthesis of 1,4-diazepine and 1,5-benzodiazepine derivatives via the reaction of ketimine intermediates with aldehydes in the presence of Keggin-type heteropolyacids (HPAs) was developed. High yields and short reaction times were obtained for both electron-releasing and electron-withdrawing substituted 1,4-diazepine and 1,5-benzodiazepines derivatives. 相似文献
72.
John Spencer Hiren Patel Jahangir Amin Samantha K. Callear Simon J. Coles John J. Deadman Christophe Furman Roxane Mansouri Philippe Chavatte Régis Millet 《Tetrahedron letters》2012,53(13):1656-1659
A 2-substituted-5-aminooxazole-4-carbonitrile library has been synthesised and modified via microwave-mediated and flow chemistries. One synthesised compound, 5-(1H-pyrrol-1-yl)-4-(1H-tetrazol-5-yl)-2-(thien-2-yl)oxazole, contains three distinct heterocycles attached to the central oxazole core, highlighting the structural diversity of this approach. Three oxazoles had micromolar ki values against cannabinoid (CB1/CB2) receptors. 相似文献
73.
Sturgeon RE Lam JW Windust A Grinberg P Zeisler R Oflaz R Paul RL Lang BE Fagan JA Simard B Kingston CT 《Analytical and bioanalytical chemistry》2012,402(1):429-438
Several techniques were evaluated for the establishment of reliable water/moisture content of single-wall carbon nanotubes. Karl Fischer titration (KF) provides a direct measure of the water content and was used for benchmarking against results obtained by conventional oven drying, desiccation over anhydrous magnesium perchlorate as well as by thermogravimetry and prompt gamma-ray activation analysis. Agreement amongst results was satisfactory with the exception of thermogravimetry, although care must be taken with oven drying as it is possible to register mass gain after an initial moisture loss if prolonged drying time or elevated temperatures (120 °C) are used. Thermogravimetric data were precise but a bias was evident that could be accounted for by considering the non-selective loss of mass as volatile carbonaceous components. Simple drying over anhydrous magnesium perchlorate for a minimum period of 8-10 days is recommended if KF is not available for this measurement. 相似文献
74.
In this paper, we present two composite Milstein methods for the strong solution of Stratonovich stochastic differential equations driven by d-dimensional Wiener processes. The composite Milstein methods are a combination of semi-implicit and implicit Milstein methods. The criterion for choosing either the implicit or the semi-implicit method at each step of the numerical solution is given. The stability and convergence properties of the proposed methods are analyzed for the linear test equation. It is shown that the proposed methods converge to the exact solution in Stratonovich sense. In addition, the stability properties of our methods are found to be superior to those of the Milstein and the composite Euler methods. The convergence properties for the nonlinear case are shown numerically to be the same as the linear case. Hence, the proposed methods are a good candidate for the solution of stiff SDEs. 相似文献
75.
Refat A. Mahmoud Ahmed A. El-Samahy Mostafa M. Rabia 《Journal of solution chemistry》1984,13(7):517-522
Iodine complexes of imidazoles in chloroform were studied by using the constant activity method. The equilibrium constants and the extinction coefficients of the complexes were determined and the results are compared with those obtained by using conventional spectral method. It was found that the equilibrium constants increase as the donor strength increases, while the extinction coefficients decrease. This behavior was interpreted in terms of molecular structure of the donor molecule. 相似文献
76.
Atıf Koca Musa Şahin Ahmet Gül Rabia Z. Uslu 《Monatshefte für Chemie / Chemical Monthly》2002,133(8):1135-1145
Summary. In this study, the electrochemical properties of metal-free and nickel-containing porphyrazines with eight tosylaminoethylthia
groups were investigated using cyclic voltammetry, double potential step chronoamperometry, double potential step chronocoulometry,
and controlled potential coulometry. Cyclic voltammetry measurements showed that both compounds exhibit two quasi-reversible and an irreversible reduction waves. The first electron transfer reaction was followed by an irreversible chemical
reaction, the second one by a reversible chemical reaction for both species. The electrode processes of metal-free and nickel-containing
porphyrazines are diffusion controlled, but the double potential step chronocoulometry measurements indicated that the nickel
porphyrazine is adsorbed at the electrode. However, a small adsorption current has no significant effect on the mass transport
mechanism of the system. Diffusion coefficients of both compounds were determined by both cyclic voltammetric and chronocoulometric
measurements. The diffusion coefficients of the reduced forms of the porphyrazines were found to be smaller than those of
the neutral forms.
Received October 29, 2001. Accepted (revised) December 17, 2001 相似文献
77.
Certification of standard reference material (SRM) 1941a, organics in marine sediment 总被引:2,自引:0,他引:2
Michele M. Schantz Bruce A. Benner Jr. Melinda J. Hays W. Robert Kelly Robert D. Vocke Jr. Rabia Demiralp Robert R. Greenberg Susannah B. Schiller Gunnar G. Lauenstein Stephen A. Wise 《Fresenius' Journal of Analytical Chemistry》1995,352(1-2):166-173
SRM 1941a, Organics in Marine Sediment, has been recently issued with certified concentrations for 23 polycyclic aromatic hydrocarbons, 21 polychlorinated biphenyl congeners, 6 chlorinated pesticides, and sulfur. Noncertified concentrations have been also reported for additional PAHs, PCB congeners, and chlorinated pesticides and for percent total organic carbon (TOC), aliphatic hydrocarbons, and trace elements. SRM 1941a is the most extensively characterized natural matrix SRM issued by the National Institute of Standards and Technology (NIST). 相似文献
78.
Rabia Zeynep Uslu Kobak Duygu Akyüz Atıf Koca 《Journal of Solid State Electrochemistry》2016,20(5):1311-1321
Metallophthalocyanines (MPcs) (M = 2H+, Zn2+, Co2+, and Cu2+) bearing diethylaminophenoxy and chloro substituents at the peripheral positions (MPc-tdea-tCl) were coated on the working electrodes with the electropolymerization and tested as electrochromic materials. Altering the metal center of MPcs affected the redox activities of MPc-tdea-tCl films. All electropolymerized MPc-tdea-tCl films behaved as conductive and redox active films in different electrolyte systems. Electrochromic properties of MPc-tdea-tCl films were investigated via the voltammetric, in situ spectroelectrochemical, and in situ spectroelectrocolorimetric measurements. H 2 Pc-tdea-tCl film did not give any electrochromic response, while ZnPc-tdea-tCl and CuPc-tdea-tCl films behave as a reasonable electrochromic material. Distinctive color changes with short response times, high optical contrast, and better optical and coulombic stabilities were only observed with CoPc-tdea-tCl film. 相似文献
79.
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