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41.
Saeed Jameh-Bozorghi Davood Nori-Shargh Seiedeh Negar Mousavi Amin Rezaei 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):839-849
Abstract Natural bond orbital (NBO) interpretation and hybrid density functional theory (hybrid-DFT: B3LYP/Def2-TZVPP)-based methods were used to investigate the impacts of the generalized anomeric effects (GAE), electrostatic, and steric interactions on the conformational properties of cis and trans isomers of 2-fluoro-, 2-chloro-, and 2-bromotetrahydrothiopyran S-oxide (1–3). The results obtained showed that the trans-axial configurations are the most stable forms of compounds 1–3. Based on the results obtained, the instability of the second lowest energy-minimum (cis-equatorial configuration, with axial S?O and equatorial C?X bonds, X = halogen atoms) increases from compound 1 to compound 3. This trend is also observed for the third lowest energy-minimum (i.e., the trans-equatorial configuration). Contrary to the trend observed for the cis- and trans-equatorial forms, the instability of the cis-axial form compared to the trans-axial form, increases from 1 to 2 but decreases slightly from 2 to 3. The correlations between the GAE, bond orders, steric effects, ΔG, Δμ, structural parameters, and conformational and configurational behaviors of compounds 1–3 have been investigated. 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
42.
Reza Fareghi-Alamdari Mohsen GolestanzadehFarima Agend Negar Zekri 《Comptes Rendus Chimie》2013,16(10):878-887
Highly sulfonated single-walled carbon nanotube-catalyzed synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes in excellent yields and very short reaction times. Sulfonated single-walled carbon nanotubes are prepared using a chemical and simple process and it characterized by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Thermal gravimetric analysis (TGA) and acid-base titration. The sulfonated single-walled carbon nanotube was easily separated by simple filtration and was recycled eight consecutive times without any loss in its activity. 相似文献
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44.
Application of Nanosized Cu0.5Co0.5Fe2O4 Spinel Ferrite as a Nanocatalyst in the Synthesis of 14‐Aryl‐14H‐dibenzo[a,j]xanthene Derivatives under Solvent‐free Conditions
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Copper and cobalt substituted spinel ferrites Cu1‐xCoxFe2O4 (0≤X≤1) have been synthesized by using hydrothermal method. The resultant spinel ferrites were systematically characterized by different techniques such as X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FT‐IR). It was indicated that all the resultant spinel ferrites obtained by the hydrothermal method had the single‐phase crystalline. The resultant spinel ferrites were employed in the synthesis of 14‐aryl‐14‐H‐dibenzo[a,j]xanthene derivatives. It was found that the nanocatalyst Cu0.5Co0.5Fe2O4 displays the best performance in the synthesis of 14‐aryl‐14H‐dibenzo[a,j]xanthenes. The catalyst was reused several times without significant loss of its activity for the preparation of desired product. In addition high yields of the products, solvent‐free conditions and reusability of the catalyst are other worthwhile advantages of the present study. 相似文献
45.
We show that a combination of two simple preprocessing steps would generally improve the conditioning of a homogeneous system of linear inequalities. Our approach is based on a comparison among three different but related notions of conditioning for linear inequalities. 相似文献
46.
Maleki Behrooz Eshghi Hossein Barghamadi Mohammad Nasiri Negar Khojastehnezhad Amir Sedigh Ashrafi Samaneh Pourshiani Omid 《Research on Chemical Intermediates》2016,42(4):3071-3093
Research on Chemical Intermediates - A powerful, magnetic, supported, acid catalyst, NiFe2O4@SiO2–H3PW12O40, was prepared by chemical support of Keggin (H3PW12O40) heteropolyacid (HPA) on... 相似文献
47.
Negar Motakef-Kazemi Seyed Abbas Shojaosadati Ali Morsali 《Journal of the Iranian Chemical Society》2016,13(7):1205-1212
This work presents an experimental investigation of drug loading in metal-organic frameworks (MOFs). Porous metal organic framework [Zn2(bdc)2(dabco)] was synthesized under solvothermal conditions. Characterization of samples was studied by IR spectroscopy, X-ray powder diffraction, thermogravimetric analysis, ultraviolet–visible spectroscopy, N2 adsorption porosimetry and scanning electron microscopy. In vitro cytotoxicity assessment and IC50 values for the human hepatoma cell (HuH7) was determined by MTT assay. Two different sizes of Zn2(bdc)2(dabco) were prepared by solvothermal method under the presence and absence of modulator. The prepared samples were used for ibuprofen loading. Ibuprofen loadings of 22 and 30 % (w/w) were obtained for samples with average diagonal sizes of 250 and 100 nm, respectively. The release of ibuprofen from these materials was prolonged for 2 and 3 weeks for 250 and 100 nm samples, respectively. The results obtained in this study revealed that two significant factors, surface area and pore size, affect ibuprofen drug loading and release. 相似文献
48.
Novel fluorescent carbon dots (CDs) for cobalt ions sensing were synthesized from 2,4,6-tris(2′-pyridyl)-s-triazine (TPTZ) and citric acid by microwave-assisted method in one pot. This sensor was water soluble, simple, sensitive and cheap. The size of the CDs was determined from transmission electron microscope image and was in the range of 10 nm. Under optimized experimental conditions, this luminescent system had stable response for Co (II) over a concentration range from 0.4 to 50 µM with a detection limit as low as 230 nM. The proposed method showed good sensitivity and selectivity with respect to interference ions. Finally, this system was used for Co (II) determination in tap water, river water and mineral water and B12 ampoule samples. 相似文献
49.
Majid Abdellahi Zahra Aslani Negar Nazemi Saeid Jabbrzare 《Chinese Journal of Physics (Taipei)》2018,56(3):880-885
The present paper was written with the aim of synthesizing zirconium ferrite nanopowders and evaluating its magnetic hyperthermia properties. A mechanical milling process along with a sintering process were conduct on the raw powders to prepare zirconium ferrite nanopowders. X-ray diffraction results confirmed a pure product and the VSM tools, showed a single domain state for the powders with a size less than 35?nm. Analysis of the samples under AC magnetic field demonstrated that mono-disperse nanoparticles met a higher value of the specific absorption rate (SAR) in comparison with multi-disperse one. Besides, according to the linear response theory the ratio of the anisotropy energy to the thermal one, as a dimensionless anisotropy parameter (σ), has a key role in the SAR values of zirconium ferrite nanopowders. 相似文献
50.
Sharifah Nurfadhlin Afifah Syed Azhar Siti Efliza Ashari Norhazlin Zainuddin Masriana Hassan 《Molecules (Basel, Switzerland)》2022,27(1)
Advanced hybrid component development in nanotechnology provides superior functionality in the application of scientific knowledge for the drug delivery industry. The purpose of this paper is to review important nanohybrid perspectives in drug delivery between nanostructured lipid carriers (NLC) and hydrogel systems. The hybrid system may result in the enhancement of each component’s synergistic properties in the mechanical strength of the hydrogel and concomitantly decrease aggregation of the NLC. The significant progress in nanostructured lipid carriers–hydrogels is reviewed here, with an emphasis on their preparation, potential applications, advantages, and underlying issues associated with these exciting materials. 相似文献