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91.
Khoobi M Alipour M Zarei S Jafarpour F Shafiee A 《Chemical communications (Cambridge, England)》2012,48(24):2985-2987
A straightforward and atom-economical base-free palladium-catalyzed regioselective direct arylation of coumarins and chromenones is devised. This protocol is compatible with a wide variety of electron-donating and -withdrawing substituents and allows construction of various biologically important flavone and neoflavone backbones. 相似文献
92.
Samaneh Kharian Nader Teymoori Mohammad A. Khalilzadeh 《Journal of Solid State Electrochemistry》2012,16(2):563-568
In this work, we describe an electrochemical method using p-chloranil as a mediator and multi-wall carbon nanotube and TiO2 as sensors for sensitive determination of epinephrine (EP) in aqueous solution at pH = 10.0. It has been found that under
optimum condition (pH 10.0) in cyclic voltammetry, the oxidation of EP occurred at a potential about 171 mV less positive
than that unmodified carbon nanotube paste electrode. The diffusion coefficient (D) and the kinetic parameters, such as electron transfer coefficient, (α) and heterogeneous rate constant (k
h) for EP were also determined using electrochemical approaches. The electrocatalytic currents increase linearly with the EP
concentration over the range 0.6–135 μM. The detection limits for EP will be equal to 0.25 μM. The relative standard deviation
percentage values for 10.0 and 15.0 μM EP were 1.7% and 1.9%, respectively. Finally, this modified electrode was also examined
as a selective, simple, and precise new electrochemical sensor for the determination of EP in real sample such as urine and
epinephrine injection solution. 相似文献
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94.
Samaneh Mahmoudi-Gom Yek Davood Azarifar Masoud Khaleghi-Abbasabadi Hassan Keypour Masoumeh Mahmoudabadi 《应用有机金属化学》2020,34(12):e5989
In this article, the synthesis of a novel and highly efficient recyclable and reusable heterogeneous nanocatalyst has been reported via the functionalizing of the Fe3O4-magnetized graphene oxide nanosheets with the N6-Schiff base Cu (II) complex (GO/Fe3O4@SPNC). The structure of this novel nanocatalyst was determined by different analytical techniques such as FTIR, FE-SEM, TEM, TGA-DTG, and VSM. The catalytic activity of the synthesized GO/Fe3O4@SPNC nanocatalyst was explored for the synthesis of several new 2H-pyrido[3′,2′:6,7]pyrano[2,3-d]pyrimidine-7-carbonitrile derivatives with excellent yields. All new derivatives were fully identified by various spectral (1H NMR, 13C NMR, FT-IR, ESI-MS) analyses. In addition, this nanocatalyst carried out satisfactory catalytic maintenance of activity and high chemical stability in the titled reactions after seven-time of recycling without substantial loss of leaching. 相似文献
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96.
Density functional theory (DFT), Bader’s theory of atoms in molecules (AIM) and natural bond orbital (NBO) calculations have been used to understand the nature of the interaction between M(H2O)6n+ (M = Mg2+, Al3+) complexes and fullerene, coronene and benzene π-systems. The interaction energies were calculated for all the compounds and corrected for the basis set superposition error (BSSE). The results showed that the above π-systems have larger interaction energies with Al(H2O)63+ than Mg(H2O)62+. Also the AIM topological parameters for the bond critical points (BCPs) between the M(H2O)6n+ cations and the fullerene, coronene and benzene π-systems confirmed that {[Al(H2O)6]3+?fullerene} has a much stronger bonding interaction than the other systems. The calculated interaction energies correlate well with both the Wiberg bond indices and the global value of charge transfers from π-systems to cations evaluated through natural population analysis. The calculations suggest that the ionic potential of the central metal ion in the M(H2O)6n+ cation and the nature of π-system are two influential factors that affect the strength and the nature of the interaction. 相似文献
97.
Sima Sedighi Mohammad T. Baei Masoud Javan Joshua Charles Ince Alireza Soltani Mohammad Hassan Jokar Samaneh Tavassoli 《Surface and interface analysis : SIA》2020,52(11):725-734
This study provides details of the electronic and optical structures and binding energies of sarin (SF) and chlorosarin (SC) with Al–N and Al–P surfaces of Al12N12 and Al12P12 nanoclusters in the gas phase. The adsorption mechanism of SF and SC on these nanoclusters containing the Al3+ central cation was studied. Optimized geometries and thermodynamic parameters of SF and SC adsorption complexes were calculated. SF and SC are chemisorbed on these nanoclusters because of the formation of PO···Al bonds. The chemical bond is formed between an oxygen atom of SF and SC and an aluminum atom of fullerene-likes (chemisorption). However, the binding energies of the complexes with the Al12N12 nanocluster are larger than these values for the Al12P12 nanocluster. The interaction enthalpy and Gibbs free energy of all studied systems were found to be negative. We can conclude that SF and SC will be adsorbed preferably on Al12N12 nanocluster. 相似文献
98.
Sakineh Asghari Fahimeh Molaee Samaneh Ramezani 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1896-1904
Deoxybenzoin undergoes a smooth reaction with acetylenic esters in the presence of triphenylphosphine to produce phosphorus ylides. Only the tert-butyl phosphorus ylide undergoes an intramolecular Wittig reaction to produce highly strained cyclobutenes in boiling toluene, which spontaneously undergoes ring-opening reactions to produce highly functionalized 1,3-dienes. The unstable ylides undergo a 1,2-proton transfer and the loss of PPh3 to produce functionalized alkenes. 相似文献
99.
Ali Sarafraz Yazdi Samaneh Raouf Yazdinezhad Jeyran Akhoundzadeh 《Journal of the Iranian Chemical Society》2013,10(4):643-651
A simple, low-cost and sensitive method is demonstrated for derivatization and extraction of iodine from milk samples using hollow fiber liquid-phase microextraction (HF-LPME) and gas chromatography-electron capture detection. Iodide ions are converted to iodine under acidic medium and in the presence of an oxidant. The generated iodine reacted with 3-pentanone in extraction vial to give 2-iodo-3-pentanone and was extracted into 4 μL of 1-octanol located in the lumen of a hollow fiber. Organic solvent was selected using one variable at a time optimization method and the other main factors affecting derivatization and HF-LPME procedures were evaluated using a Taguchi’s L16 (45) orthogonal array. Under optimal conditions, the method showed low limit of detection (0.5 ng mL?1), wide linear range (1–2,000 ng mL?1) with good correlation coefficient (0.9997) and acceptable relative standard deviation (4.6 %, n = 5). Finally, the developed method was successfully applied for determination of iodide in real samples including infant milk formulas and cow milk with reasonable relative recoveries (99.8–110.5 %). 相似文献
100.
Samaneh Mozaffari Mohsen Dehghan Mahmood Borhanizarandi Mohamad Reza Nateghi 《Journal of Solid State Electrochemistry》2014,18(3):655-663
A hybrid of polymer/dispersed single-wall carbon nanotubes was utilized in networking a novel composition of gel electrolyte in dye-sensitized solar cells. The gel is composed of polyethylene glycol, polyvinyl pyrrolidone, single-wall carbon nanotubes, and I?/I3 ? as electrolyte. Formation of the less conductive polyiodide species in electrolyte was prohibited by the addition of single-wall carbon nanotubes leading to the excellent photovoltaic behavior of the cell under simulated standard illumination of the fabricated device owing to the increased open circuit voltage (0.47 V). Electrochemical impedance spectroscopy was employed to quantify the charge transport resistance and the electron lifetime at the TiO2 conduction band. Charge transport resistances at the TiO2/dye/electrolyte interface were determined for the cells consisting of the non-gel reference and our new gel electrolytes, and it was indicated that the charge recombination between injected electrons and electron acceptors (I3 ?) in the redox electrolyte was remarkably retarded. Electrochemical parameters obtained by the fitting showed all of the resistances increased as compared to liquid electrolyte dye-sensitized solar cells that can be related to the increase in viscosity of the gel, which hinders the ionic transportation through the electrolyte. These results were also confirmed by the electron lifetime analyses. The characteristic peak shifted to a lower frequency in the Bode phase plot for the cell containing gel electrolyte which is an indication of a longer electron lifetime in comparison with that of the cell containing very conventional liquid electrolyte. 相似文献