排序方式: 共有75条查询结果,搜索用时 15 毫秒
31.
Mitra Ghassemzadeh Samira Bahemmat Masoomeh Mahmoodabadi Babak Rezaii-Rad Hassan Hosseini Monfared Effat Mottefakeri Bernhard Neumüller 《Polyhedron》2010
The reaction of AMTT (AMTT = 4-amino-3-methyl-1,2,4-triazol-5-thione, HL1) with palladium(II) chloride and triphenylphosphane as a co-ligand in acetonitrile afforded the mononuclear PdII-complex [(PPh3)Pd(HL1)Cl]Cl·2CH3CN (1). The complex [(PPh3)Pd(HL1)I]Cl·1/2H2O (2) was prepared via halogen exchange between 1 and sodium iodide in methanol/acetonitrile. The first binuclear palladium(II) complex containing singly deprotonated HL1, [(PPh3)2ClPd(L1)Pd(PPh3)Cl]Cl·1/3H2O·CH3OH (3), was prepared by the reaction of HL1 with palladium(II) chloride and triphenylphosphane in the presence of sodium acetate in methanol. 相似文献
32.
Maryam Hajjami Arash Ghorbani-Choghamarani Zahra Karamshahi Masoomeh Norouzi 《催化学报》2014,35(2):260-263
Tribromo melamine has been found to be an efficient and green organocatalyst for the acetylation and formylation reactions of alcohols with acetic anhydride and ethyl formate at room temperature and under mild reaction conditions. 相似文献
33.
Abdoljavad Novinrooz Masoomeh Sharbatdaran Hassan Noorkojouri 《Central European Journal of Physics》2005,3(3):456-466
Thin layers of tungsten trioxide have been prepared from an aqueous solution of peroxotungstic acid (PTA) using the sol-gel
method. Compositional, structural and optical characteristics of WO3 coated on indium tin oxide (ITO) conductive glass substrates were studied using X-ray diffractometery (XRD), cyclic voltammetery
(CV), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Monoclinic and triclinic crystalline
structures for thin film and powdered WO3 were confirmed by XRD analysis. SEM micrograph of annealed samples revealed micro cracks due to a decrease in density and
a contraction of layers. EDX analysis showed that 1∶2 ratio of oxygen and tungsten atoms in the prepared films is obtained
at heat treatment temperatures higher than 200 °C. Furthermore, the annealed samples showed very good electrochromic behavior
in cyclic voltammetery studies. Refractive index “n” and extinction coefficient “k” values were found to be reduced by increasing
the wavelength and decreasing the temperature. 相似文献
34.
35.
SPE coupled with dispersive liquid–liquid microextraction followed by GC with flame ionization detection for the determination of ultra‐trace amounts of benzodiazepines 下载免费PDF全文
Masoomeh Ghobadi Yadollah Yamini Behnam Ebrahimpour 《Journal of separation science》2014,37(3):287-294
SPE combined with dispersive liquid–liquid microextration was used for the extraction of ultra‐trace amounts of benzodiazepines (BZPs) including, diazepam, midazolam, and alprazolam, from ultra‐pure water, tap water, fruit juices, and urine samples. The analytes were adsorbed from large volume samples (60 mL) onto octadecyl silica SPE columns. After the elution of the desired compounds from sorbents with 2.0 mL acetone, 0.5 mL of eluent containing 40.0 μL chloroform was injected rapidly into 4.5 mL pure water. After extraction and centrifugation, 2 μL of the sedimented phase was injected into a GC equipped with a flame ionization detector. Several parameters affecting this process were investigated and optimized. Under the optimal conditions, LODs ranged from 0.02 to 0.05 μg/L, a linear dynamic range of 0.1–100 μg/L and relative SDs in the range of 4.4–10.7% were attained. Very high preconcentration factors ranging from 3895–7222 were achieved. The applicability of the method for the extraction of BZPs from different types of complicated matrices, such as tap water, fruit juices, and urine samples, was studied. The obtained results reveal that the proposed method is a good technique for the extraction and determination of BZPs in complex matrices. 相似文献
36.
A wide variety of alcohols and phenols were protected as trimethylsilyl ethers using 1,1,1,3,3,3-hexamethyl disilazane catalyzed by aspartic acid as a non-toxic,metal-free,and green organocatalyst at room temperature in acetonitrile under mild and heterogeneous conditions.The procedure is operationally simple and the silylated product was obtained in high yield and purity. 相似文献
37.
ABSTRACTThe variability of planar rings in Si4X4 (X?=?F, Cl, Br, I) molecules caused by the pseudo-Jahn–Teller impact (PJTE) was evaluated as an original PJTE work. Optimisation and the following frequency calculations in these molecules illustrated that in high-symmetry planar (with D4h symmetry) geometry, all of these compounds were unstable and their structures were puckered to lower C2h symmetry stable geometry. Furthermore, the vibronic coupling interaction between 1A1g ground and the first 1Eg excited states through (1A1g?+?1Eg) ? eg PJTE problem was the cause of non-planarity of the four-member ring and the symmetry breaking phenomenon in those series. The calculated gaps (Δ) between the ground state and the Eg excited state, the vibronic coupling (F) and ground state primary force constant values (k1) were obtained from the numerical fitting of the ground state adiabatic potential energy surface with the analytical expressions of these molecules. Finally, natural bond analysis (NBO) was used for the design of the strongest interaction and natural atomic charges of these structures. 相似文献
38.
An efficient and high-yielding synthesis of N~2-arylaminopyrimidine-5-carbonitrile derivatives starting from arylamines and 2-methylthio-pyrimidine-5-carbonitriIe derivatives has been developed in the presence of cesium carbonate as basic reagent.This new protocol showed high chemical tolerance for a range of functional groups,and only the methylthio substituent on C2 of the pyrimidine ring was replaced with arylamine derivatives under the reaction conditions. 相似文献
39.
Cu(II)–Schiff base complex‐functionalized magnetic Fe3O4 nanoparticles: a heterogeneous catalyst for various oxidation reactions 下载免费PDF全文
Cu(II)–Schiff base complex‐functionalized magnetic Fe3O4 nanoparticles were prepared and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy techniques. This compound acts as a highly active and selective catalyst for the oxidation of sulfides and thiols. These reactions can be carried out in ethanol or solvent‐free conditions in the presence of hydrogen peroxide with complete selectivity and very high conversion under mild reaction conditions. The designed catalytic system prevents effectively the over‐oxidation of sulfides to sulfones. Separation and recycling can also be easily done using a simple magnetic separation process. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
40.
Abdolraouf Samadi-Maybodi S. Masoomeh Pourali Mohsen Tafazzoli 《Journal of solution chemistry》2009,38(2):159-169
27Al NMR spectroscopy is a powerful tool for the study of coordination and solvation in both aqueous and nonaqueous solutions.
In this study, the complexes coexisting upon dissolution of AlCl3 in acidic acetone + methanol solutions are shown to consist essentially of mixed hexacoordinated species of the general formula
[Al(CH3OH)6−n
(CH3COCH3)
n
]3+ (n=1,2 and 3), all exhibiting distinctly different 27Al shielding effects. The relative populations of the various mixed species are found to be highly dependent upon the acetone:methanol
mole ratio that in the more acetone-rich mixtures with aluminum become appreciably coordinated by acetone. The results demonstrate
that the key factor for the formation of acetone-containing species in acidic methanolic solutions is having the CH3COCH3:CH3OH mole ratio at 3:1. 相似文献