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171.
Mohammad Navid Soltani Rad Somayeh Behrouz Mohammad Mahdi Doroodmand Abdollah Movahediyan 《Tetrahedron》2012,68(38):7812-7821
The synthesis and characterization of copper-doped silica cuprous sulfate (CDSCS) as a new and efficient heterogeneous nano catalyst are described. CDSCS has been fully characterized by different microscopic, spectroscopic and physical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic forced microscopy (AFM), X-ray diffraction (XRD), inductively coupled plasma (ICP) analysis, thermogravimetric analysis (TGA) and FT-IR. CDSCS is proved to be a useful heterogeneous nano catalyst in Cu(I)-catalyzed ‘Click’ cycloaddition of organic azides with terminal alkynes. CDSCS catalyzes the 1,3-dipolar cycloaddition reactions of β-azido alcohols and alkynes at room temperature, in THF/H2O (1:1, v/v) solution. Using CDSCS, 1,4-disubstituted 1,2,3-triazole adducts are mainly obtained, in good to excellent yields and in short reaction times. These compounds have featural resemblance to β-adrenoceptor blocking agents. CDSCS was approved as a chemically and thermally stable nano catalyst that can be reused for many consecutive trials without a significant decline in its reactivity. 相似文献
172.
Mathematical Programming - In this work, we study the optimization landscape of the non-convex matrix sensing problem that is known to have many local minima in the worst case. Since the existing... 相似文献
173.
Somayeh Fotoohi Mohammad Kazem Moravvej-Farshi Rahim Faez 《Applied Physics A: Materials Science & Processing》2014,116(1):295-301
Electronic and transport properties of 11 zigzag graphene nanoribbons (11-z-GNRs) with two types of 3D-paired pentagon–heptagon defects (3D-PPHDs) are studied using density functional theory combined with non-equilibrium Green’s function method. The C ad-dimers that have been introduced to z-GNRs to form these 3D-PPHDs have induced local strains forcing the C-bonds in the ad-dimers to hybridize in sp3-like rather than sp2-like orbitals. Such transformations that cause extra electrons to accumulate around the 3D-PPHDs are responsible for the variations in the electronic and transport properties of the defected z-GNRs. Density of states (DOS) for 11-z-GNRs containing either type of 3D-PPHDs, compared with that of the pristine 11-z-GNR, exhibits a peak at a particular energy level below the Fermi level, within its first plateau. Each peak, corresponding to a dip in the related zero-bias conductance profile, is attributed to electrons trapped in the localized states around the same energy level. The current–voltage (I–V) characteristics are almost linear for 11-z-GNR defected by either type of 3D-PPHD. Presence of a 3D-PPHD, made by addition of a single C ad-dimer, above an 11-z-GNR super-cell decreases its average conductance by 10.7 %, while a 3D-PPHD made by addition of two C ad-dimers to the opposite sides of the same 11-z-GNR super-cell decreases its conductance by 23 %. 相似文献
174.
Saeedi Mina Raeisi-Nafchi Maryam Sobhani Sepideh Mirfazli Seyedeh Sara Zardkanlou Mahsa Mojtabavi Somayeh Faramarzi Mohammad Ali Akbarzadeh Tahmineh 《Molecular diversity》2021,25(4):2399-2409
Molecular Diversity - In this work, various imidazo[1,2-a]pyridines linked to carbamate moiety were designed, synthesized, and evaluated for their α-glucosidase inhibitory activity. Among... 相似文献
175.
Six‐coordinated vanadium(IV) complexes with tridentate task‐specific ionic liquid Schiff base ligands: Synthesis,characterization and effect of ionic nature on catalytic activity
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By reaction of 5‐(chloromethyl)salicylaldehyde with triphenylphosphine and N‐methylimidazole in two separate reactions, salicylaldehydetriphenylphosphonium chloride (S2) and salicylaldehydemethylimidazolinium chloride (S3) were prepared. Reaction of 2‐(aminomethyl)pyridine with these aldehydes resulted in the task‐specific ionic liquid Schiff base ligands L1 and L2, respectively. Then six‐coordinated vanadium(IV) Schiff base complexes of VO(acac)L1–4 were synthesized by reactions of these tridentate Schiff base ligands and VO(acac)2 in 1:1 stoichiometry. The aldehydes, ligands and VO(acac)L1–4 complexes were characterized using infrared, 1H NMR, 13C NMR, 31P NMR, UV–visible and mass spectroscopies, as well as elemental analysis. Paramagnetic property of the complexes was also studied using magnetic susceptibility measurements. The complexes were used as catalysts in epoxidation of cyclooctene and oxidation of methylphenyl sulfide and the reaction parameters were optimized. The effect of the ionic nature of the complexes was investigated in these oxidation reactions. The catalytic activity of the complexes could be varied by changing the ionic (cationic or anionic) character of VO(acac)L1–4 catalysts in which counter anion variation showed a greater effect than cationic moiety variation. 相似文献
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Selective aerobic oxidative coupling of thiols that are catalyzed by La(III)-substituted 5-oxopyrrolidine-2-carboxylic acid (Glp) immobilized on SBA-15 (SBA-15@Glp–La; SBA = Santa Barbara amorphous) was studied. Using SBA-15@Glp–La, the complete conversion was achieved at room temperature in the presence of air without producing any over-oxidized yields. SBA-15@Glp–La was prepared by post-grafting technique. 5-Oxopyrrolidine-2-carboxylic acid (Glp) condensation followed by La(III) impregnation caused this La(III)-grafted 5-oxopyrrolidine-2-carboxylic acid (Glp) to immobilize on SBA-15. This SBA-15@Glp–La catalyst shows excellent catalytic activity in the selective aerobic oxidative coupling of thiols. Effects of amount of the catalyst, polarity of the solvent, effects of substrate, and catalyst reusability were investigated. It has been observed that seven repetitive reaction cycles did not cause any appreciable loss in the catalytic activity of this catalyst. The catalyst characterization by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, thermal gravimetric analysis, transmission electron microscopy, inductively coupled plasma, elemental mapping, and N2 adsorption–desorption is reported. The procedure developed is heterogeneous and environmentally benign. 相似文献
178.
Soleimani Ebrahim Torkaman Sara Sepahvand Heshmatollah Ghorbani Somayeh 《Molecular diversity》2019,23(3):739-749
Molecular Diversity - In this research, synthesis and characterization of new surface-functionalized magnetic silica nanoparticles are reported. The magnetic silica nanoparticle was synthesized by... 相似文献
179.
Gholamhosseini-Nazari Mahdi Esmati Somayeh Safa Kazem D. Khataee Alireza Teimuri-Mofrad Reza 《Research on Chemical Intermediates》2019,45(4):1841-1862
Research on Chemical Intermediates - In this study, a novel magnetically recoverable Fe3O4@SiO2-BenzIm-Fc[Cl]/ZnCl2 nano-particle was synthesized using a simple chemical coprecipitation approach.... 相似文献
180.
Ali Maleki Abbas Ali Jafari Somayeh Yousefi 《Journal of the Iranian Chemical Society》2017,14(8):1801-1813
A new biopolymer cellulose-based magnetic heterogeneous catalyst, MgFe2O4/cellulose/SO3H nanocomposite, was prepared. Fourier-transform infrared spectra, X-ray diffraction, energy-dispersive X-ray, field-emission scanning electron microscopy, thermal analysis (TG, DTG and DSC), dynamic light scattering and vibrating sample magnetometer measurements have been used to characterize the catalyst. Then, it was applied efficiently as an inexpensive and green catalyst in two multicomponent syntheses of polysubstituted tetrahydropyridines and dihydropyrimidinones under solvent-free conditions. The nanocatalyst can be recovered and reused several times without significant loss of catalytic activity. 相似文献