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61.
Palladium‐anchored multidentate SBA‐15/di‐urea nanoreactor: A highly active catalyst for Suzuki coupling reaction
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Sahar Rohani Ghodsi Mohammadi Ziarani Alireza Badiei Abolfazl Ziarati Maryam Jafari Alireza Shayesteh 《应用有机金属化学》2018,32(8)
Modification of mesoporous silica was carried out by reaction of SBA‐15 with di‐urea‐based ligand. Next, with the help of this ligand, palladium ions were anchored within the multidentate SBA‐15/di‐urea pore channels with high dispersion. The SBA‐15/di‐urea/Pd catalyst was characterized using various techniques. Theoretical calculations indicated that each palladium ion was strongly interacted with one nitrogen and two oxygen atoms from the multidentate di‐urea ligand located in SBA‐15 channels and these interactions remained during the catalytic cycle. These results are in good agreement with those of hot filtration test: the palladium ions have very high stability against leaching from the SBA‐15/di‐urea support. The catalytic performance of SBA‐15/di‐urea/Pd nanostructure was examined for the Suzuki coupling reaction of phenylboronic acid and electronically diverse aryl halides under mild conditions with a minimal amount of Pd (0.26 mol%). Compared to previous reports, this protocol afforded some advantages such as short reaction times, high yields of products, catalyst stability without leaching, easy catalyst recovery and preservation of catalytic activity for at least six successive runs. 相似文献
62.
A novel functionalized SBA-15 mesoporous material was prepared through co-condensation of tetraethylorthosilicate with an 8-hydroxyquinoline-5-sulfonamide-modified organosilane precursor in the presence of P123 as structure-directing agent. After removal of template, the obtained material was characterized by powder X-ray diffraction (XRD), nitrogen adsorption-desorption, Fourier transform infrared (FT-IR), thermal analysis (TGA-DTA), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and elemental analysis. Then, aluminum quinolate complex was attached covalently to this functionalized SBA-15 by using coordinating ability of grafted 8-HQ and its emission spectra showed a slightly blue shift in comparison with AlQ(3) complex. 相似文献
63.
Saeed?Dadvar Hossein?TavanaiEmail author Hamid?Dadvar Mohammad?Morshed Farhad?E.?Ghodsi 《Journal of Sol-Gel Science and Technology》2011,59(2):269-275
UV radiation causes serious damage to skin, and a protective system capable of absorbing or reflecting UV radiation is required
to protect skin. This paper describes the UV protection and photocatalytic properties of TiO2 nanofilm coated electrospun polyacrylonitrile (PAN) nanofibrous mats with various nanofiber diameter and area density. The
mats were coated by sol–gel process. The results of this research showed that sol–gel is capable of coating porous nanofibrous
mats with a weight increase as low as 0.8%. The TiO2 nanofilm coated on the nanofibrous mats has a considerable effect on its UV protection. The UV protection factor (UPF) of
the mats increases with decreasing nanofiber diameter. In fact decreasing the diameter of nanofibers of the TiO2 nanofilm coated PAN nanofibrous mats increases their photocatalytic activity. Moreover, this research showed that TiO2 nanofilm produced through sol–gel process on the PAN nanofibers has a crystalline structure. The UPF of the nanofibrous mat
coated with a TiO2 nanofilm via sol–gel process can be classified as excellent. 相似文献
64.
l-Dopa is the intermediate precursor of the neurotransmitter dopamine. Unlike dopamine, l-dopa easily enters the central nervous system. l-Dopa, as one of the catecholamines, is widely used as a source of dopamine in the treatment of most patients with Parkinson’s disease and epilepsy. Graphene (GR) is ideally suited for implementation in electrochemical applications due to its reported large electrical conductivity, large surface area, unique heterogeneous electron transfer rate, and low production costs. This work reports the synthesis of GR using a modified Brodie method and its application for the electrochemical determination of l-dopa in real samples. Electrochemical measurements were performed at glassy carbon electrode modified with graphene (GR/GCE) via drop casting method. Cyclic voltammograms of l-dopa at GR/GCE showed an increased current intensity compared with GCE. All the measurements were done in phosphate buffer solution 0.1 M (pH 6.2) and the oxidation peak was observed at 0.27 V vs. Ag/AgCl. The effect of scan rate showed that oxidation of l-dopa on GR/GCE was surface controlled. The oxidation peak current of l-dopa gradually increased with increasing accumulation time from 0 to 300 s and accumulation potential from 0.0 to 0.3 V and reached the maximum current response at 240 s and 0.2 V for the accumulation time and accumulation potential, respectively. Voltammetric peak currents showed a linear response for l-dopa concentration in the range of 0.04 to 79 μM and a detection limit of 0.022 μM (22 nM). The relative standard deviation for five determinations of 50 μM l-dopa was 0.52 %. 相似文献
65.
Efficient One‐Pot Solvent‐Free Synthesis of 1H‐Pyrazolo[1,2‐b]phthalazine‐5,10‐diones Catalyzed by Sulfonic Acid Functionalized Nanoporous Silica (SBA‐Pr‐SO3H)
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Ghodsi Mohammadi Ziarani Nina Hosseini Mohtasham Alireza Badiei Negar Lashgari 《中国化学会会志》2014,61(9):990-994
A green protocol has been developed for the synthesis of 1H‐pyrazolo[1,2‐b]phthalazine‐5,10‐diones by one‐pot cyclocondensation reaction of phthalhydrazide, aromatic aldehydes, and malononitrile or ethyl cyanoacetate using sulfonic acid functionalized SBA‐15 (SBA‐Pr‐SO3H) as a heterogeneous solid acid catalyst under solvent‐free conditions. 相似文献
66.
An efficient and simple method for the synthesis of bis(4‐hydroxycoumarin)methanes has been achieved through a one‐pot condensation of aryl aldehydes and 4‐hydroxycoumarin in the presence of nanoporous solid acid catalyst of SBA‐Pr‐SO3H with pore size of 6 nm. Excellent yields, short reaction times, reusability of the catalyst and simple workup are advantages of this synthetic procedure. 相似文献
67.
Tahereh Ahmadi Ghodsi Mohammadi Ziarani Parisa Gholamzadeh Hoda Mollabagher 《Tetrahedron: Asymmetry》2017,28(5):708-724
Asymmetric multicomponent reactions (AMCRs) include the reaction of three or more reactants simultaneously to produce chiral products that they have some advantages containing simple procedures, saving time and energy, and being environmentally friendly processes. AMCRs have seen much development and their potent synthetic approaches are discussed in this review. 相似文献
68.
Mohammad Sadegh Alireza Abbasi Ghodsi Mohammadi Ziarani 《Journal of luminescence》2010,130(11):2072-2075
The CaWO4:Ln3+@SiO2 (Ln=Tb, Dy and Ho) nanoparticles were synthesized via a combustion process at 800 °C, using citric acid as chelating agent and fuel, ammonium nitrate as fuel, boric acid as flux material and silica as supports. The persistent phosphor nanoparticles were characterized by X-ray diffraction (XRD), reflectance UV-vis and fluorescence spectroscopy (PL) and transmission electron microscopy (TEM) techniques. XRD patterns indicated that crystalline calcium tungstate with scheelite structure was produced. The reflectance UV-vis spectra showed the broad absorption band of groups and the PL spectra showed the wide excitation band, broad emission band of and characteristic emissions of Ln3+ ions. The average particle sizes were determined by TEM, which are about 50 nm. 相似文献
69.
Amir Koolivand Alireza Badiei Pezhman Arab Ghodsi Mohammadi Ziarani 《Journal of the Iranian Chemical Society》2016,13(7):1315-1324
A nanoporous carbon (CMK-3) was synthesized and used to adsorb 2-phenylethanol (PEA) from aqueous solutions. The characterization of CMK-3 by N2 adsorption isotherm revealed the formation of a nanoporous carbon with average pore diameter and surface area of 3.34 nm and 1268 m2 g?1, respectively. Column-like particle morphology of CMK-3 was observed from scanning electron microscope images. To evaluate the feasibility of CMK-3 as a potential PEA adsorbent, batch adsorption experiments were conducted for aqueous PEA solutions. The results showed that CMK-3 is an efficient sorbent for the separation of PEA from water. The optimized adsorbent doses were found to be 0.3 and 2.2 g L?1 for 30 and 300 mg L?1 PEA, respectively. Our studies about the effect of pH on CMK-3 adsorption capacity revealed that the adsorption capacity increased at lower pH due to the protonation of PEA. Three adsorption models, Langmuir, Freundlich and Temkin were used to describe the adsorption isotherms. Thermodynamic parameters such as ΔG 0, ΔH 0, and ΔS were also evaluated, and it was found that the sorption process was spontaneous, endothermic, and physical in nature. The adsorption kinetics was investigated in detail and the pseudo-second-order kinetic equation fitted the experimental data very well. The mechanistic study by Weber-Morris model revealed that the overall adsorption process was simultaneously governed by external mass transfer and intraparticle diffusion. Almost all (97 %) adsorbed PEA was successfully recovered into ethanol which is a common solvent in fragrance industry. CMK-3 was proved to be a promising adsorbent for the adsorption-recovery of PEA from aqueous solution. 相似文献
70.
Nader Alharbi Zara Ghodsi Hossein Hassani 《Mathematical Methods in the Applied Sciences》2016,39(13):3750-3757
We present a new approach for removing the nonspecific noise from Drosophila segmentation genes. The algorithm used for filtering here is an enhanced version of singular spectrum analysis method, which decomposes a gene profile into the sum of a signal and noise. Because the main issue in extracting signal using singular spectrum analysis procedure lies in identifying the number of eigenvalues needed for signal reconstruction, this paper seeks to explore the applicability of the new proposed method for eigenvalues identification in four different gene expression profiles. Our findings indicate that when extracting signal from different genes, for optimised signal and noise separation, different number of eigenvalues need to be chosen for each gene. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献