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1.
Research on Chemical Intermediates - Metal–carbenoids from α-diazocarbonyl compounds are well-known reactive intermediates with a long history of useful applications in synthetic organic...  相似文献   
2.
The spectroscopic properties of Nω-nitro-l-arginine were investigated by FT-IR, UV-VIS, and 1H NMR spectra. Geometrical parameters and energies were calculated using the density functional theory (DFT) B3LYP method with the 6-311G basis set. Geometrical optimization of the molecule has been performed, vibrational spectra have been calculated, and fundamental vibrations have been determined from the total energy distribution (TED) of the vibrational modes. The HOMO-LUMO analysis is carried out for various electric fields (0.0–0.025 A?1). The HOMO-LUMO gap is decreased while increasing the electric field. The calculated quantum chemical parameters are calculated and correlated to the inhibition efficiency, A Mullliken population was also important for determining local reactivity by indicating reactive centers and identifying potential nucleophilic and electrophilic attack sites. Charge transfer occurs inside the compound based on the HOMO LUMO gap. Calculations of DFT were evaluated in their ability to predict inhibition efficiency.  相似文献   
3.
Stable silver nanoparticles have been synthesized using gum karaya acting as both reducing and stabilizing agent without using any synthetic reagent. The reaction is performed using water, which is an environmentally safe solvent. This reaction was carried out in an autoclave at a pressure of 15 psi and 120 °C temperature by varying the time. The influence of different parameters such as time, change of concentration of silver nitrate and concentration of gum karaya on the formation of silver nanoparticles has been studied. The synthesized silver nanoparticles are characterized by UV–Vis spectroscopy, FTIR, XRD and TEM. UV–Vis analysis of the sample confirmed the formation of silver nanoparticles exhibiting a sharp peak at a wavelength of 420 nm. TEM micrographs showed the formation of well-dispersed silver nanoparticles of size 2–4 nm. The antimicrobial activity of silver nanoparticles stabilized in gum karaya is tested against Escherichia coli, Micrococcus luteus and is found to be possessing inhibiting property. The silver nanoparticles stabilized in gum karaya exhibited very good catalytic activity and the kinetics of the reaction was found to be pseudo first order with respect to the 4-nitrophenol.  相似文献   
4.
Titled compounds undergo selective N‐C cleavage on treatment with sodium hydroxide in ethanol affording a series of novel isatin‐based spiroazetidinones.  相似文献   
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6.
Dawn-dusk features of the plasmasphere are examined for intervals in February and September 1969, using electrostatic probe data ofN e andT e from the ISIS-I satellite. Clear plasmatrough formation is seen in the vicinity of 70° geomagnetic latitude in both dawn and dusk sectors in the 1500–3500 km region, but the plasmatrough is absent in the altitude range 500–1500 km. The plasmatrough minimum near 70°φ exhibits no asymmetry between dawn and dusk sectors in its latitudinal position. TheT e peak associated with the plasmatrough is more pronounced in the dawn sector. DawnN e is less than duskN e, but dawnT e exceeds duskT e. The influence of processes in the magnetosphere in causing these features is examined.  相似文献   
7.
Summary The flow of a micropolar fluid for sinusoidally deforming boundaries is discussed in detail. The velocity and microrotation fields and the streamfunction are determined and plotted under the assumption of small deformations.
Zusammenfassung Die Strömung einer mikropolaren Flïssigkeit mit sinusoidaler Verformung der Begrenzung wird ausführlich diskutiert. Die Geschwindigkeits- und Mikrorotationsfelder und die Stromfunktion werden mit der Annahme einer kleinen Verformung bestimmt und graphisch dargestellt.
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8.
A new, efficient and highly diastereoselective approach for the synthesis of 1,2,3,5-tetraacetylcarba-alpha-D-lyxofuranose from D-ribose is reported via one-pot conversion of to using Tebbe reagent which involves a cascade reaction sequence of methylenation, cleavage of isopropyl group, carbocyclization and again methylenation.  相似文献   
9.
Synthesis and stabilization of FeCo nanoparticles   总被引:1,自引:0,他引:1  
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10.
Kinetics of oxidation of 24 S‐Arylmercaptoacetic acids (SAMA) by pyridinium chlorochromate (PCC) have been studied in acidmedium. The product of oxidation is the corresponding thiophenol. The rate data of meta‐ and para‐substituted acids have been correlated well with σI, σRo values and the meta‐compounds correlate well with F,R values. The reaction constants are negative and of smaller magnitudes. Further, the ortho‐substituted acids show a good correlation with triparametric equation involving Taft's σI and σRo and charton's steric parameter v. There is no considerable steric contribution to the total orthosubstituent effect. Based on these observations, the mechanism involving the formation of protonated arylsulfinylacetic acid intermediate, followed by an intramolecular rearrangement leading to the product thiophenol has been proposed. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 683–688, 1999  相似文献   
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