Search for: halogenation
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    Palladium-catalyzed carbamate-directed regioselective halogenation: A route to halogenated anilines

    , Article Journal of Organic Chemistry ; Volume 81, Issue 9 , 2016 , Pages 3868-3876 ; 00223263 (ISSN) Matloubi Moghaddam, F ; Tavakoli, G ; Saeednia, B ; Langer, P ; Jafari, B ; Sharif University of Technology
    American Chemical Society  2016
    This study describes an efficient method for ortho-selective halogenation of N-arylcarbamates under mild conditions for the first time. Although being weakly coordinating, N-arylcarbamates act very well as a removable directing group for activation of C-H bonds. The developed procedure results in extremely valuable halogenated N-arylcarbmates that can further be hydrolyzed to halogenated anilines. The obtained reaction conditions showed broad scope and wide functional group tolerance. All the products were formed in good yields with extremely high selectivity  

    Crystal Engineering and Interaction Energy Calculation of Some New Rhenium(I) Tricarbonyl Complexes Bearing Bidentate NN-donor Ligand: Transmetallation of Rhenium(I) Tricarbonyl and Copper(I) Iodide

    , M.Sc. Thesis Sharif University of Technology Mahmoudi, Soheil (Author) ; Kia, Reza (Supervisor)
    In this research, synthesis, structural and theoretical studies of rhnium(I) tricarbonyl complexes with general formula, fac-[Re(CO)3(NN)X] in which NN´ is chelating bidentate diimine ligand and X = Cl, Br, and OCOCF3 ligands were studied. The synthesized complexes were characterized by 1H-NMR and FTIR spectroscopic methods and their solid state structures were determined by X-ray diffraction analysis. Then, the reaction of the synthesized rhenium complexes were studied by copper(I) iodide. Crystal structure determination by single-crystal X-ray diffraction allows us to fully examine the intramolecular and intermolecular interactions. We also investigated the energy of different... 

    Halogen-lithium exchange reaction using an integrated glass microfluidic device: an optimized synthetic approach

    , Article Organic Process Research and Development ; Volume 21, Issue 3 , 2017 , Pages 292-303 ; 10836160 (ISSN) Zeibi Shirejini, S ; Mohammadi, A ; Sharif University of Technology
    American Chemical Society  2017
    A telescoped approach was developed for the efficient synthesis of methoxybenzene through the generation of an unstable intermediate reagent, based on the Br-Li exchange reaction of p-bromoanisole and n-BuLi, followed by its reaction with water. In the first stage, p-methoxyphenyllithium was synthesized and consumed immediately in the second stage. For this purpose, an integrated glass microfluidic device was fabricated using laser ablation followed by the thermal fusion bonding method. The impact of various parameters, including solvent, reaction time, molar ratio, concentration of reagents, and flow rates were investigated to achieve the highest yield of the desired product, leading to an... 

    Light Induced Curing of TiO2 Mesoporous Layer Utilized in Perovskite Solar Cells

    , M.Sc. Thesis Sharif University of Technology Zamanpour, Fahimeh (Author) ; Taghavinia, Nima (Supervisor)
    The efficiencies of perovskite solar cells have increased rapidly in recent years and reached about 22%. Which hopes to make this type of solar cell more functional. In the normal structure of perovskite solar cells, the presence of mesoporous TiO2 mesoporous layer has increased sustainability and efficiency. To create this layer, a common method is placing the sample in a furnace for 30 minutes at 450°C-500°C. Using the furnace, in addition to being time consuming, has a high energy consumption. In this study, we tried to create a TiO2 mesoporous layer with the help of lighting. To create TiO2 mesoporous layer, What causes porosity in the layer is the removal of ethyl cellulose and create... 

    Study on Structure, Mechanical Properties, and Flammability of PC/ABS

    , M.Sc. Thesis Sharif University of Technology Alaei, Yasaman (Author) ; Bagheri, Reza (Supervisor) ; Seyed Reyhani, Morteza (Supervisor)
    Polycarbonate (PC) is known as one of the engineering plastics with remarkable mechanical properties, but the application of this polymer is limited due to its high notch sensitivity. Blending polycarbonate with other polymers such as acrylonitrile butadiene styrene (ABS) is a method to resolve this disadvantage. PC/ABS blends are commonly used in automotive industry, electrical and electronic devices. As PC and ABS are not completely miscible, a variety of compatibilizers are used to achieve a suitable microstructure and high engineering properties. Considering crucial applications of PC/ABS blends, different flame retardants are also used to reduce the flammability. These flame retardants... 

    Greener, nonhalogenated solvent systems for highly efficient Perovskite solar cells

    , Article Advanced Energy Materials ; Volume 8, Issue 21 , 25 July , 2018 ; 16146832 (ISSN) Yavari, M ; Mazloum Ardakani, M ; Gholipour, S ; Tavakoli, M. M ; Turren Cruz, S. H ; Taghavinia, N ; Gratzel, M ; Hagfeldt, A ; Saliba, M ; Sharif University of Technology
    Wiley-VCH Verlag  2018
    All current highest efficiency perovskite solar cells (PSCs) use highly toxic, halogenated solvents, such as chlorobenzene (CB) or toluene (TLN), in an antisolvent step or as solvent for the hole transporter material (HTM). A more environmentally friendly antisolvent is highly desirable for decreasing chronic health risk. Here, the efficacy of anisole (ANS), as a greener antisolvent for highest efficiency PSCs, is investigated. The fabrication inside and outside of the glovebox showing high power conversion efficiencies of 19.9% and 15.5%, respectively. Importantly, a fully nonhalogenated solvent system is demonstrated where ANS is used as both the antisolvent and the solvent for the HTM.... 

    Carbon dioxide: A waste product in the catalytic cycle of α-ketoglutarate dependent halogenases prevents the formation of hydroxylated by-products

    , Article Journal of Physical Chemistry B ; Volume 113, Issue 1 , 2009 , Pages 12-14 ; 15206106 (ISSN) De Visser, S. P ; Latifi, R ; Sharif University of Technology
    American Chemical Society  2009
    We present the first density functional theory study on α-ketoglutarate dependent halogenase and focus on the mechanism starting from the iron(IV)-oxo species. The studies show that the high-valent iron(IV)-oxo species reacts with substrates via an initial and rate determining hydrogen abstraction that is characterized by a large kinetic isotope effect (KIE) of 26.7 leading to a radical intermediate. This KIE value is in good agreement with experimental data. The reaction proceeds via two-state reactivity patterns on competing quintet and septet spin state surfaces with close lying hydrogen abstraction barriers. However the septet spin radical intermediate gives very high barriers for... 

    An efficient two-step approach for improvement of graphene aerogel characteristics in preparation of supercapacitor electrodes

    , Article Journal of Energy Storage ; Volume 17 , 2018 , Pages 465-473 ; 2352152X (ISSN) Jokar, E ; Shahrokhian, S ; zad, A. I ; Asadian, E ; Hosseini, H ; Sharif University of Technology
    Elsevier Ltd  2018
    We fabricated a high rate capability supercapacitor based on fluorine-doped graphene-carbon nanotubes aerogel network (G-CNT-F). Based on the electrochemical impedance spectroscopy data, the fluorination decreases the charge transfer resistance of graphene sheets, while CNTs act as spacer in the 3D structure. Therefore, both treatments improved the electrochemical properties of the resulted aerogel. Based on the Fourier transform infrared spectroscopy and XPS results, these excellent performances are attributed to semi-ionic bonds between fluorine and carbon. The specific capacitance of the graphene aerogel showed 78% decrease, when discharge current increases from 2 to 40 mA, while the... 

    Mechanical strength of CFRP and GFRP composites filled with APP fire retardant powder exposed to elevated temperature

    , Article Fire Safety Journal ; Volume 115 , 2020 Shekarchi, M ; Majdabadi Farahani, E ; Yekrangnia, M ; Ozbakkaloglu, T ; Sharif University of Technology
    Elsevier Ltd  2020
    Ammonium polyphosphate (APP) is one of the most widely used halogen-free flame retardant, added in various resins to improve the fire properties, such as flame and smoke spread ratings and LOI, of fiber-reinforced polymer (FRP) composites. This paper experimentally investigates the effects of using APP, as a fire-retardant filler, on mechanical properties (i.e. ultimate tensile, flexural, and bond strength) of glass fiber-reinforced polymer (GFRP) and carbon fiber-reinforced polymer (CFRP) composites. Based on two fiber types (i.e. carbon and glass) and three different APP mass fractions in resin (i.e. 0, 20, and 40% of total weight of matrix), six sets of specimens were prepared for each... 

    Evaluation of trichloroethylene degradation by starch supported Fe/Ni nanoparticles via response surface methodology

    , Article Water Science and Technology ; Volume 73, Issue 4 , 2016 , Pages 935-946 ; 02731223 (ISSN) Nikroo, R ; Alemzadeh, I ; Vossoughi, M ; Haddadian, K ; Sharif University of Technology
    IWA Publishing 
    In this study, degradation of trichloroethylene (TCE), a chlorinated hydrocarbon, using starch supported Fe/Ni nanoparticles was investigated. The scanning electron microscope images showed applying water soluble starch as a stabilizer for the Fe/Ni nanoparticles tended to reduce agglomeration and discrete particle. Also the mean particle diameter reduced from about 70 nm (unsupported Fe/Ni nanoparticle) to about 30 nm. Effects of three key independent operating parameters including initial TCE concentration (10.0-300.0 mg L-1), initial pH (4.00-10.00) and Fe0 dosage (0.10-2.00) g L-1 on TCE dechlorination efficiency in 1 hour were analysed by employing response surface methodology (RSM).... 

    Novel fluoridated silk fibroin/ TiO2 nanocomposite scaffolds for bone tissue engineering

    , Article Materials Science and Engineering C ; Volume 82 , 2018 , Pages 265-276 ; 09284931 (ISSN) Johari, N ; Madaah Hosseini, H. R ; Samadikuchaksaraei, A ; Sharif University of Technology
    Elsevier Ltd  2018
    It is known that Fluoride ions strongly affect bone mineralization and formation. In the present study, the engineered bone tissue scaffolds are fabricated using silk fibroin (SF) and flouridated TiO2 nanoparticles. TiO2 nanoparticles are modified by fluoride ions, and different levels (0, 5, 10, 15 and 20 wt%) of the fluoridated TiO2 nanoparticles (TiO2-F) were subsequently added to the SF matrix through phase separation method to prepare silk fibroin/flouridated TiO2 nanocomposite scaffolds (SF/TiO2-F). Phase structure, functional groups, morphology and mechanical properties of the obtained scaffolds were evaluated by X-ray diffraction method (XRD), Fourier transform infrared spectroscopy... 

    Synthesis and properties of novel fluorinated polyamides based on noncoplanar sulfoxide containing aromatic bis(ether amine)

    , Article Polymer Journal ; Volume 41, Issue 3 , 2009 , Pages 174-180 ; 00323896 (ISSN) Shockravi, A ; Abouzari Lotf, E ; Javadi, A ; Taheri, S ; Sharif University of Technology
    A novel sulfoxide containing bis(ether amine) monomer, 2,2'-sulfoxide- bis[4-methyl(2-trifluoromethyl)4-aminophenoxy) phenyl ether] (M2), was synthesized from the halogen displacement of 2-chloro-5-nitrobenzotrifluoride with dibenzosulfoxide (DH) in the presence of potassium carbonate, followed by catalytic reduction of bis(ether nitro) intermediate with Zinc/Ammonium chloride. A series of organic-soluble poly(ether amide)s (PA1-7) bearing sulfoxide and electronwithdrawing trifiuoromethyl group were synthesized from bis(ether amine) with various aromatic diacids (1-7) via a direct polycondensation with triphenyl phosphite and pyridine. The resulting polymers had inherent viscosities ranging... 

    Nanomedicine and advanced technologies for burns: Preventing infection and facilitating wound healing

    , Article Advanced Drug Delivery Reviews ; Volume 123 , 2018 , Pages 33-64 ; 0169409X (ISSN) Mofazzal Jahromi, M. A ; Sahandi Zangabad, P ; Moosavi Basri, S. M ; Sahandi Zangabad, K ; Ghamarypour, A ; Aref, A. R ; Karimi, M ; Hamblin, M. R ; Sharif University of Technology
    Elsevier B.V  2018
    According to the latest report from the World Health Organization, an estimated 265,000 deaths still occur every year as a direct result of burn injuries. A widespread range of these deaths induced by burn wound happens in low- and middle-income countries, where survivors face a lifetime of morbidity. Most of the deaths occur due to infections when a high percentage of the external regions of the body area is affected. Microbial nutrient availability, skin barrier disruption, and vascular supply destruction in burn injuries as well as systemic immunosuppression are important parameters that cause burns to be susceptible to infections. Topical antimicrobials and dressings are generally...