排序方式: 共有60条查询结果,搜索用时 31 毫秒
51.
Mohammad Abbasi Najmeh Nowrouzi Saeedeh Ghassab Borazjani 《Tetrahedron letters》2017,58(45):4251-4254
A sulfur transfer reagent was produced in situ upon stirring a mixture of KCN and CS2 in DMF at r.t. for 15 min, which after heating with an alkyl halide or aryl halide and CuI gave the corresponding symmetric dialkyl or diaryl disulfide, respectively, in high to excellent yields. 相似文献
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Javad Safari Soheila Gandomi-Ravandi Saeedeh Shariat 《Journal of the Iranian Chemical Society》2016,13(8):1499-1507
In the present investigation, we have developed a novel technique to prepare azines using nano-WCl6 loaded on Montmorillonite K10 clay as a highly active catalyst. A variety of aldehydes and ketones were efficiently converted to the corresponding azines using catalytic amounts of nanosized WCl6/Mont. K10 under mild conditions. The nanostructures of WCl6 loaded on Mont. K10 as solid acid catalyst have been prepared by solid dispersion method. The advantages of this catalyst are rapid completion of the reactions, simplicity of performance, lack of pollution and mild and green reaction conditions. The morphologies, structure, and chemical components of parent and modified clay were successfully characterized using SEM, FT-IR, CV, XRD and EDX measurements. 相似文献
53.
In the present study, the adsorption and decomposition of diazomethane (DAZM) on the surface of (6,0) zigzag silicon carbide nanotube (SiCNT) are investigated using density functional theory calculations. The geometry structures of the three stable configurations, adsorption energies and electronic properties of DAZM adsorption on the surface of SiCNT are investigated. It was found that the DAZM molecule is decomposed over the surface of (6,0) SiCNT with activation energy (Eact) of 0.523 eV. The curvature effect on the adsorption energies of the DAZM molecule is also considered by studying (5,0) and (7,0) SiCNTs. The results display that DAZM adsorption over smaller diameter of SiCNT is thermodynamically more favourable than larger one. 相似文献
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Navid Amini Saeedeh Mazinani Seyed-Omid Ranaei-Siadat Mohammad Reza Kalaee Saeed Hormozi Kaveh Niknam Nasrin Firouzian 《Applied biochemistry and biotechnology》2013,170(1):91-104
In this work, polyacrylamide/multi-walled carbon nanotubes (MWCNT) solution is electrospun to nanocomposite nanofibrous membranes for acetylcholinesterase enzyme immobilization. A new method for enzyme immobilization is proposed, and the results of analysis show successful covalent bonding of enzymes on electrospun membrane surface besides their non-covalent entrapment. Fourier transform infrared spectroscopy, mechanical and thermal investigations of nanofibrous membrane approve successful cross-linking and enzyme immobilization. The enzyme relative activity and kinetic on both pure and nanocomposite membranes is investigated, and the results show proper performance of designed membrane to even improve the enzyme activity followed by immobilization compared to free enzyme. Scanning electron microscopy images show nanofibrous web of 3D structure with a low shrinkage and hydrogel structure followed by enzyme immobilization and cross-linking. Moreover, the important role of functionalized carbon nanotubes on final nanofibrous membrane functionality as a media for enzyme immobilization is investigated. The results show that MWCNT could act effectively for enzyme immobilization improvement via both physical (enhanced fibers’ morphology and conductivity) and chemical (enzyme entrapment) methods. Figure
Mechanism for APTS surface modification of nanofibrous nanoweb for enzyme immobilization 相似文献
56.
A suite of branched-chain pyrogallol[4]arene (Pg) macrocycles, most of which show activity in bilayer membranes, has been prepared and studied by X-ray crystallography. The little-known branched side-chain Pgs include 2-propyl, 2-butyl, 2-pentyl, 3-pentyl, 3-heptyl, 4-heptyl, 5-nonyl and cyclohexyl. The Pgs form self-assembled structures having bilayer, capsule or, in one case, a nanotube morphology. The nanotube structure observed for C-(di-n-ethyl)pyrogallol[4]arene was confirmed by X-ray structure analysis and by transmission and scanning electron microscopies. 相似文献
57.
Ebadullah Asadi Saman Azodi-Deilami Majid Abdouss Saeedeh Khaghani 《Applied biochemistry and biotechnology》2012,167(7):2076-2087
In this study, we used novel synthetic conditions of precipitation polymerization to obtain nanosized cyproterone molecularly imprinted polymers for application in the design of new drug delivery systems. The scanning electron microscopy images and Brunauer?CEmmett?CTeller analysis showed that molecularly imprinted polymer (MIP) prepared by acetonitrile exhibited particles at the nanoscale with a high degree of monodispersity, specific surface area of 246?m2?g?1, and pore volume of 1.24?cm3?g?1. In addition, drug release, binding properties, and dynamic light scattering of molecularly imprinted polymers were studied. Selectivity of MIPs was evaluated by comparing several substances with similar molecular structures to that of cyproterone. Controlled release of cyproterone from nanoparticles was investigated through in vitro dissolution tests and by measuring the absorbance by HPLC-UV. The pH dissolution media employed in controlled release studies were 1.0 at 37?°C for 5?h and then at pH 6.8 using the pH change method. Results show that MIPs have a better ability to control the cyproterone release in a physiological medium compared to the non molecularly imprinted polymers (NMIPs). 相似文献
58.
Hadi Beitollahi Alireza Mohadesi Saeedeh Khalilizadeh Mahani Hassan Karimi-Maleh Ali Akbari 《Ionics》2012,18(7):703-710
A carbon paste electrode modified with 5-amino-3??,4??-dimethoxy-biphenyl-2-ol and carbon nanotubes was used for the sensitive voltammetric determination of norepinephrine (NE). The electrochemical response characteristics of the modified electrode toward NE, acetaminophen (AC), and folic acid (FA) were investigated by cyclic and square wave voltammetry (SWV). The results show an efficient catalytic activity of the electrode for the electrooxidation of NE, which leads to lowering its overpotential more than 160?mV. The modified electrode exhibits an efficient electron-mediating behavior together with well-separated oxidation peaks for NE, AC, and FA. Under the optimum pH of 7.0 in 0.1?M phosphate buffer solution, the SWV anodic peak current showed a linear relation vs. NE concentration in the range of 15.0 to 1,000.0???M with a detection limit of 8.0???M. 相似文献
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Maryam RaeisianAsl Saeedeh Sarabadani Tafreshi Nora H. de Leeuw 《Molecules (Basel, Switzerland)》2023,28(1)
Density functional theory calculations have been performed to study the effect of replacing lead by alkaline earth metals on the stability, electronic and optical properties of the formamidinium lead triiodide (FAPbI3) (111) and (100) surfaces with different terminations in the form of FAPb1-xAExI3 structures, where AE is Be, Mg or Ca. It is revealed that the (111) surface is more stable, indicating metallic characteristics. The (100) surfaces exhibit a suitable bandgap of around 1.309 and 1.623 eV for PbI5 and PbI6 terminations, respectively. Increases in the bandgaps as a result of Mg- and Ca-doping of the (100) surface were particularly noted in FAPb0.96Ca0.04I3 and FAPb0.8Ca0.2I3 with bandgaps of 1.459 and 1.468 eV, respectively. In the presence of Be, the band gap reduces critically by about 0.315 eV in the FAPb0.95Be0.05I3 structure, while increasing by 0.096 eV in FAPb0.96Be0.04I3. Optimal absorption, high extinction coefficient and light harvesting efficiency were achieved for plain and doped (100) surfaces in the visible and near UV regions. In order to improve the optical properties of the (111)-PbI3 surface in initial visible areas, we suggest calcium-doping in this surface to produce FAPb0.96Ca0.04I3, FAPb0.92Ca0.08I3, and FAPb0.88Ca0.12I3 structures. 相似文献