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61.
Ali Ramazani Nahid Shajari Amir Tofangchi Mahyari Mehdi Khoobi Yavar Ahmadi Ali Souldozi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2496-2502
Reactions of (N-isocyanimino)triphenylphosphorane with 1,1,1-trifluoroacetone in the presence of aromatic (or heteroaromatic) carboxylic acids (3-methylbenzoic acid, 1-naphthalenecarboxylic acid, 2-naphthalenecarboxylic acid, 2-furancarboxylic acid, and 2-thiophenecarboxylic acid) proceed smoothly at room temperature and in neutral conditions to afford sterically congested 1,1,1-trifluoro-2-(5-aryl-1,3,4-oxadiazol-2-yl)-2-propanol derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions, and no side reactions were observed. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
62.
The variations of the open circuit voltages (OCVs) were studied in a passive air-breathing direct methanol fuel cell with an air-breathing cathode using Nafion 115 as the electrolyte membrane. The effects of some operating parameters such as cell temperature, cell orientation, and also methanol concentration on the OCV of fabricated fuel cell were investigated experimentally. The experimental results showed that the OCV values depend strongly on the cell orientation, cell temperature, and methanol concentration. The OCV values decrease with an increase in methanol concentration and cell temperature. Also, the OCV values in vertical orientation are lower than the OCV values in other orientations. 相似文献
63.
In recent years ionic liquids (ILs) have attracted much interest because of their widespread use in various fields. Several trimerization and oligomerization catalysts have been evaluated in ILs with different organic–inorganic hybrid structures. High catalytic activity and selectivity, easy product separation, and recycling of the catalyst are the advantages of a biphasic catalyst system compared to the homogeneous catalysts. In this study, the influence of IL counter-anions on activity and selectivity of the ethylene trimerization catalysts based on Cr-SNS-R was investigated. All synthesized materials were characterized using Fourier-transform infrared spectroscopy, 1H NMR, 13C NMR, UV–Vis. spectroscopy, thin-layer chromatography, and elemental analysis (CHNS). In ethylene trimerization reaction, the dodecyl substituent in the SNS ligand exhibited better activity and selectivity than the butyl substituent. The results revealed that the presence of BF4− as a counter-anion in the IL led to an increase in activity and selectivity compared to Br− and I− counter-anions. It was found that the BF4− counter-anion plays a conclusive role in the development of 1-hexene activity and selectivity to a maximum amount of 71,132 g1-C6/(gCr × h) and more than 99%, respectively. Finally, the catalyst was reused thrice without losing its 1-hexene selectivity. 相似文献
64.
Raana Kashfi‐Sadabad Laura Gonzalez‐Fajardo Derek Hargrove Bahar Ahmadi Daniel Munteanu Sina Shahbazmohamadi Michael Jay Xiuling Lu 《Particle & Particle Systems Characterization》2019,36(4)
Nonspecific high‐energy radiation for treatment of metastatic ovarian cancer is limited by damage to healthy organs, which can be mitigated by the use of radiosensitizers and image‐guided radiotherapy. Gold (Au) and tantalum oxide (TaOx) nanoparticles (NPs), by virtue of their high atomic numbers, find utility in the design of bimetallic NP systems capable of high‐contrast computed tomography (CT) imaging as well as a potential radiosensitizing effect. These two radio‐dense metals are integrated into dendritic mesoporous silica NPs (dMSNs) with radial porous channels for high surface‐area loading of therapeutic agents. This approach results in stable, monodispersed dMSNs with a uniform distribution of Au on the surface and TaOx in the core that exhibits CT attenuation up to seven times greater than iodine or monometallic dMSNs without either TaOx or Au. Tumor targeting is assessed in a metastatic ovarian cancer mouse model. Ex vivo micro‐CT imaging of collected tumors shows that these NPs not only accumulate at tumor sites but also penetrate inside tumor tissues. This study demonstrates that after intraperitoneal administration, rationally designed bimetallic NPs can simultaneously serve as targeted contrast agents for imaging tumors and to enhance radiation therapy in metastatic ovarian cancer. 相似文献
65.
Novel functionalized graphene adsorbent was prepared and characterized using different techniques. The prepared adsorbent was applied for the removal of cadmium ions from aqueous solution. A response surface methodology was used to evaluate the simple and combined effects of the various parameters, including adsorbent dosage, pH, and initial concentration. Under the optimal conditions, the cadmium removal performance of 70% was achieved. A good agreement between experimental and predicted data in this study was observed. The experimental results revealed of cadmium adsorption with high linearity follow Langmuir isotherm model with maximum adsorption capacity of 502 mg g?1, and the adsorption data fitted well into pseudo‐second order model. Thermodynamic studies showed that adsorption process has exothermic and spontaneous nature. The recommended optimum conditions are: cadmium concentration of 970 mg L?1, adsorbent dosage of 1 g L?1, pH of 6.18, and T = 25 °C. The magnetic recovery of the adsorbent was performed using a magnetic surfactant to form a noncovalent magnetic functionalized graphene. After magnetic recovery of the adsorbent both components (adsorbent and magnetic surfactant) were recycled by tuning the surface charges through changing the pH of the solution. Desorption behavior studied using HNO3 solution indicated that the adsorbent had the potential for reusability. 相似文献
66.
Mahdieh Yahyazadehfar Enayatollah Sheikhhosseini Sayed Ali Ahmadi Dadkhoda Ghazanfari 《应用有机金属化学》2019,33(9)
In this study, Co3O4 nanocatalysts were constructed in environmentally appropriate conditions using controlled, effective, and facile microwave method. The final nanostructures were characterized by SEM, XRD, and TEM analyses. The products had a small size distribution, homogeneous morphology, and crystallographic structures associated with the formation of Co3O4 nanostructures. Moreover, EDS mapping analysis confirmed the existence of Co and O elements in the final structure, and the magnetic properties of the samples were investigated by VSM. The application of this nanostructure in a catalytic process was further examined, and the results suggested that it could be used as a novel candidate for the synthesis of arylidene barbituric and Meldrum,s acid through Knoevenagel condensation of aldehydes by barbituric and Meldrum,s acid in aqueous media. The high yield of these nanocatalysts would be justified by the nature of the nanostructure as well as the experimental procedure developed in this study, which affected the physicochemical features of the products. 相似文献
67.
68.
Mwsleh Mwhmadi Mehdi Kamali Jamal Rashidiani Omid Rezai Kaveh Moradi Ashkan Faridi Khadijeh Eskandari 《Journal of Cluster Science》2014,25(6):1577-1587
NiO and CuO nanostructures were synthesized successfully via simple and fast microwave approach. Olive oil was chose as surfactant for stabilizing nanostructures. Different parameters such as microwave time and power and olive oil concentration were investigated on product size and morphology. The products were characterized with X-ray diffraction pattern, scanning electron microscopy, transmission electron microscopy and energy dispersive spectrometry analysis. 相似文献
69.
70.
Application of chromium‐doped fullerene as a carrier for thymine and uracil nucleotides: Comprehensive density functional theory calculations
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Ali Shokuhi Rad Sadegh Mehdi Aghaei Elaheh Aali Majid Peyravi Mohsen Jahanshahi 《应用有机金属化学》2018,32(2)
The interactions of the nucleobases thymine (C5H6N2O2) and uracil (C4H4N2O2) with Cr‐doped C20 fullerene (C19Cr) are investigated by performing density functional theory calculations. The adsorption of these nucleobases on C19Cr leads to two distinct geometries (P1 and P2) differing in the orientation of the nucleobases. The interaction of the nucleobases with the C19Cr nanocluster is highly exothermic, revealing that they are chemically adsorbed on C19Cr. The results show that the binding energy of the thymine–C19Cr complex is slightly higher than that of the uracil–C19Cr complex. In addition, the P2 geometry is more stable compared to P1 due to the higher binding energy in the former configuration. However, based on the results of natural bond orbital and frontier molecular orbitals analyses, the C19Cr nanocage has higher reactivity with the nucleobases in P1 geometry in comparison with P2 due to the larger charge transfer and orbital hybridization in the former geometry. Moreover, the band gap of the C19Cr nanocage decreases after interaction with the nucleobases, and interestingly the impact is more pronounced for P1 geometry, confirming the higher sensitivity of C19Cr to the nucleobases in P1 geometry. Our findings reveal the promising potential of C19Cr as an organometallic carrier for nucleobases thymine and uracil. 相似文献