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    Efficient recyclable catalytic system for deoxygenation of sulfoxides: Catalysis of ionic liquid-molybdenum complexes in ionic liquid solution

    , Article New Journal of Chemistry ; Volume 36, Issue 4 , Dec , 2012 , Pages 971-976 ; 11440546 (ISSN) Bagherzadeh, M ; Ghazali Esfahani, S ; Sharif University of Technology
    2012
    Abstract
    Three newly synthesized room temperature ionic liquids containing molybdate anion, [DMIm][MoO 2(NCS) 4], [RPy][MoO 2(NCS) 4] (R = butyl or decyl), and previously reported [BMIm][MoO 2(NCS) 4] were used as catalysts for the reduction of sulfoxides. For facilitating the recyclability of the catalysts, the ionic liquids [RMIm][PF 6] and [RPy][PF 6] (RMIm = 1-n-alkyl-3-methylimidazolium, RPy = 1-n-alkylpyridinium) were applied as ionic solvents and toluene is used as solvent for the organic phase. Molybdenum salts immobilized in RTILs constituted a reusable and efficient heterogeneous catalyst system. A maximum conversion (>99%) was achieved for reduction of diphenyl sulfoxide to diphenyl... 

    Molybdenum oxo-peroxo complex: A very fast catalyst for oxidation and reduction of sulfur-based compounds

    , Article Catalysis Communications ; Volume 23 , June , 2012 , Pages 14-19 ; 15667367 (ISSN) Bagherzadeh, M ; Haghdoost, M. M ; Amini, M ; Derakhshandeh, P. G ; Sharif University of Technology
    2012
    Abstract
    We have evaluated the catalytic activity of a molybdenum(VI) oxo-peroxo complex through the oxidation and reduction of sulfur-based compounds. Arylalkyl, diaryl and dialkyl sulfides are selectively oxidized to corresponding sulfoxides, with tert-butyl hydroperoxide (TBHP), in the presence of MoO(O 2)(phox) 2 complex as catalyst. This molybdenum complex was also found to be an efficient catalyst for the deoxygenation of sulfoxides to sulfides with PPh 3 in excellent yields and chemoselectivity  

    Melatonin as a powerful bio-antioxidant for reduction of graphene oxide

    , Article Journal of Materials Chemistry ; Volume 21, Issue 29 , 2011 , Pages 10907-10914 ; 09599428 (ISSN) Esfandiar, A ; Akhavan, O ; Irajizad, A ; Sharif University of Technology
    2011
    Abstract
    Graphene is usually synthesized through deoxygenation of graphene oxide (GO) by hydrazine as the most common and one of the strongest reducing agents. But, due to the high toxicity of hydrazine, it is not a promising reductant in large-scale production of graphene. Here, for the first time, we used melatonin (MLT), as a powerful antioxidant and a biocompatible competitor of hydrazine in reduction of GO suspension. X-ray photoelectron spectroscopy (XPS), current-voltage and optical characteristics of the sheets indicated that the deoxygenation efficiency of the GO suspensions by MLT and under heating in an alkaline condition for 3 h was comparable with the efficiency obtained by hydrazine in... 

    Hydrogen-rich water for green reduction of graphene oxide suspensions

    , Article International Journal of Hydrogen Energy ; Volume 40, Issue 16 , 2015 , Pages 5553-5560 ; 03603199 (ISSN) Akhavan, O ; Azimirad, R ; Gholizadeh, H. T ; Ghorbani, F ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    Abstract H2-rich water as a green antioxidant was applied for deoxygenation of graphene oxide (GO) suspensions. The ability of H2-rich water for deoxygenation of GO sheets was found comparable to the ability of hydrazine (as a standard and powerful reductant), using X-ray photoelectron spectroscopy. In fact, the O/C ratio of GO sheets could be reduced from 0.51 to 0.21 and 0.16 by H2-rich water and hydrazine, respectively. More importantly, while C-N bond formation is one of the side effects of GO reduction by hydrazine, no chemical C-N bond was found on the H2-water-reduced GO (rGO) sheets. This also resulted in a better restoration of the graphitic structure of the H2-water-rGO, as... 

    Genotoxicity of graphene nanoribbons in human mesenchymal stem cells

    , Article Carbon ; Volume 54 , 2013 , Pages 419-431 ; 00086223 (ISSN) Akhavan, O ; Ghaderi, E ; Emamy, H ; Akhavan, F ; Sharif University of Technology
    2013
    Abstract
    Single-layer reduced graphene oxide nanoribbons (rGONRs) were obtained through an oxidative unzipping of multi-walled carbon nanotubes and a subsequent deoxygenation by hydrazine and bovine serum albumin. Human mesenchymal stem cells (hMSCs) were isolated from umbilical cord blood and used for checking the concentration- and time-dependent cyto- and geno-toxic effects of the rGONRs and reduced graphene oxide sheets (rGOSs). The cell viability assay indicated significant cytotoxic effects of 10 μg/mL rGONRs after 1 h exposure time, while the rGOSs exhibited the same cytotoxicity at concentration of 100 μg/mL after 96 h. The oxidative stress was found as the main mechanism involved in the...