排序方式: 共有9条查询结果,搜索用时 15 毫秒
1
1.
Designing and introducing novel wheel-shaped supramolecular as host complexes with new magnetic properties is the theme of the day. So in this study, new eight binuclear chromium (III) complexes, as models of real chromium-wheel host complexes, were designed based on changing of bridged-ligands and exchange coupling constants (J) of them were calculated using the broken symmetry density functional theory approach. Substitution of fluorine ligand in fluoro-bridged model [Cr2F(tBuCO2)2(H2O)2(OH)4]?1 by halogen anions (Cl?, Br? and I? ) decreased the antiferromagnetic exchange coupling between Cr(III) centres such that by going from F? to I? the J values became more positive. In the case of hydroxo-bridged model [Cr2OH(tBuCO2)2(H2O)2(OH)4]?1, replacement of hydroxyl by methoxy anion (OMe?) strengthened the antiferromagnetic property of the complex but substitution by sulfanide (SH?) and amide (NH2?) anions weakened it and changed the nature of complexes to ferromagnetic. Because of their different magnetic properties, these new investigated complexes can be suggested as interesting synthetic targets. Also, the J value changes due to ligand substitution were evaluated and it was found that the Cr–X bond strength and partial charges of involved atoms were the most effective factors on it. 相似文献
2.
3.
Mohseni-Salehi Motahare S. Taheri-Nassaj Ehsan Hosseini-Zori Maryam 《Research on Chemical Intermediates》2018,44(3):1945-1962
Research on Chemical Intermediates - In the present study different titania/hydroxyapatite nanocomposites were successfully synthesized via a combination of sol–gel and precipitation methods.... 相似文献
4.
5.
Mohammad Mirzaii Teyeb Kakavand Motahare Talebi Saeed Rajabifar 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(1):261-267
Natural iron electrodeposition on copper substrate was studied with the aim of production of cobalt-55 radionuclide. 55Co seems well suited for PET imaging due to its high abundance of positron decay (I
β+ = 76%), its relatively long half-life (T
1/2 = 17.5 h) and its mean positron energy (E
avg = 570 keV). The electrodeposition experiments were carried out by chloride bath. Operating parameters such as pH, temperature,
current density and amount of the electrolyte components are also optimized. The optimum conditions of the iron electrodeposition
were follows: 8 g/L FeCl2, 2 g/L CaCl2, pH = 1, DC current density of 21.3 A/dm2 with a bath temperature of 75 °C temperature and 20% current efficiency. SEM photomicrographs demonstrated fine-grained structure
of the deposit obtained from the optimum bath. The electroplated iron-target was irradiated with 29.5 MeV protons at current
of 100 μA for 1 h and yields of about 31.25 MBq/μAh were experimentally obtained. 相似文献
6.
7.
Mohammad Zakarianezhad Hamid Reza Masoodi Motahare Shool 《Phosphorus, sulfur, and silicon and the related elements》2016,191(7):1063-1068
A stepwise reaction mechanism between triphenylphosphine 1 and dialkyl acetylenedicarboxylates 2 in the presence of a SH-acid, such as 2-aminothiophenol 3, has been investigated theoretically with B3LYP method using 6-311++G(d,p) basis set. Potential energies of all structures participating along the reaction path have been evaluated. For all the reactions investigated, the first step was recognized to be the rate-determining step. Quantum mechanical calculations clarified the existence of reaction product as a mixture of two E- or Z-geometrical isomers, and indicate which one of them represents the major form. The effect of subsituated alkyl groups on the potential energy surfaces was investigated. Also, the natural bond orbital method was applied for better understanding the molecular interactions. 相似文献
8.
Further Insight into the Mechanism of the Novel Multicomponent Reactions Involving Isoquinoline and Dimethyl Acetylenedicarboxylate in the Presence of 3‐Methylindole: Theoretical and Experimental Approach 下载免费PDF全文
The kinetics of the reactions among isoquinoline, dimethyl acetylenedicarboxylate, and 3‐methyl indole (as NH‐acid) was studied using UV spectrophotometry. The overall rate constant (kov) was evaluated from the slope of the plot of kobs versus reactant concentration. A large deal of useful information was obtained from the study of the effects of solvent, temperature, and reactants and concentration on the reaction rates. Based on experimental data and theoretical concepts, the reaction's first step (k1) was recognized as the rate‐determining step. Theoretical studies were performed to evaluate potential energy surfaces of all components participated in the reaction mechanism. Furthermore, the proposed mechanism was confirmed by the obtained results. The probable reaction path and product configuration were suggested based upon the theoretical results. 相似文献
9.
Zakarianezhad Mohammad Makiabadi Batoul Habibi-Khorassani Sayyed Mostafa Shool Motahareh Eslamlou Masoomeh 《Research on Chemical Intermediates》2018,44(4):2653-2665
Research on Chemical Intermediates - The mechanism of the multicomponent reaction between tert-butyl isocyanide and dimethyl acetylenedicarboxylate in presence of ethanethiol and thiophenol (as... 相似文献
1