Search for: manganese
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    Synthesis of dipyroromethanes in water and investigation of electronic and steric effects in efficiency of olefin epoxidation by sodium periodate catalyzed by manganese tetraaryl and trans disubstituted porphyrin complexes

    , Article Journal of Porphyrins and Phthalocyanines ; Volume 23, Issue 6 , 2019 , Pages 671-678 ; 10884246 (ISSN) Bagherzadeh, M ; Adineh Jonaghani, M ; Amini, M ; Mortazavi Manesh, A ; Sharif University of Technology
    World Scientific Publishing Co. Pte Ltd  2019
    Condensation of pyrrole with various aldehydes in the presence of BF3•etherate as an acid catalyst in water provides good yield of some dipyrromethanes. Prolongation of the reaction time with aldehydes substituted by electron-donating (mesityl) or electron-withdrawing (2,6-dichlorophenyl) groups on the ortho positions of the phenyl did not lead to decomposition or scrambling. Manganese trans disubstituted porphyrin complexes which derive from various dipyrromethanes and manganese tetraaryl porphyrin complexes including various substituents with different steric and electronic properties show good catalytic activity in epoxidation of alkenes by NaIO4 in the presence of imidazole (ImH). The... 

    The change in the chemical composition and toughness of API 5L-X70 welds by addition of titanium

    , Article International Journal of Modern Physics B ; Volume 23, Issue 6-7 , 2009 , Pages 1209-1216 ; 02179792 (ISSN) Beidokhti, B ; Koukabi, A. H ; Dolati, A ; He, P ; Sharif University of Technology
    The objective of this work was to study the influence of titanium variations on the API 5L-X70 steel weld metal properties. The relationship between microstructure and toughness of the weld deposit was studied by means of full metallographic, longitudinal tensile and Charpy-V notch tests on the specimens cut transversely to the weld beads. The best combination of microstructure and impact properties was obtained in the range of 0.02-0.05% titanium. By further increasing of titanium content, the microstructure was changed from a mixture of acicular ferrite, grain-boundary ferrite, Widmanstätten ferrite to a mixture of acicular ferrite, grain-boundary ferrite, bainite and ferrite with M/A... 

    Solid phase regeneration of carbonyl compounds by oxidative cleavage of carbon-nitrogen double bonds with molecular oxygen at room temperature

    , Article Letters in Organic Chemistry ; Volume 3, Issue 2 , 2006 , Pages 121-122 ; 15701786 (ISSN) Hashemi, M. M ; Akhbari, M ; Karimi Jaberi, Z ; Sharif University of Technology
    Montmorillonite K10-supported manganese(II) chloride was found to be an efficient and convenient catalyst for the oxidative cleavage of oximes, phenylhydrazones and semicarbazones to the corresponding carbonyl compounds with molecular oxygen. © 2006 Bentham Science Publishers Ltd  

    Oxidation of thiols to bisulfides by oxygen in presence of cobalt(ii) and manganese(ii) salts of 4-aminobenzoic acid supported on silica gel

    , Article Monatshefte fur Chemie ; Volume 135, Issue 1 , 2004 , Pages 41-43 ; 00269247 (ISSN) Hashemi, M. M ; Karimi Jaberi, Z ; Sharif University of Technology
    A mixture of cobalt(II) and manganese(II) salts of 4-aminobenzoic acid supported on silica gel catalyses the oxidation of thiols to disulfides in the presence of oxygen or air  

    Cobalt and Manganese Salts of p-Aminobenzoic Acid Supported on Silica Gel: A Versatile Catalyst for Oxidation by Molecular Oxygen

    , Article Monatshefte fur Chemie ; Volume 134, Issue 3 , 2003 , Pages 411-418 ; 00269247 (ISSN) Hashemi, M. M ; Ahmadibeni, Y ; Sharif University of Technology
    A 1:1 molar ratio of the cobalt and manganese salts of p-amino benzoic acid supported on silica gel is an effective catalyst for the oxidation of various organic compounds in reasonable yields using molecular oxygen. The catalyst can be reused several times  

    Synthesis and Catalytic Properties of Novel Manganese (III)-oxazine Complex in Oxidation of Sulfides and Alcohols

    , M.Sc. Thesis Sharif University of Technology Mohammadlou, Ali Akbar (Author) ; Bagherzadeh, Mojtaba (Supervisor)
    In this study new manganese(III) complexes of phox [Mn(phox)2(MeOH)2](ClO4), (phox= 2-(2` hydroxyphenyl)-5,6-dihydro-1,3-oxazine) have been synthesized and characterized with CHN,NMR and IR.The six-membered bidentate (N,O) oxazine ligand have been widely used throughout organometallic and inorganic chemistry, and are particularly important in homogeneous catalysis. The presence of N and O donor sites in oxazines may modify significantly the ligand roles for the variation of steric and electronic properties. Therefore, such systems are worth exploring for new catalytic uses . Catalytic oxidation reactions provide excellent alternatives for the use of stoichiometric reagents like urea... 

    Selective oxidation of sulfides and olefins by a manganese (III) complex containing an N,O-type bidentate oxazine ligand

    , Article Journal of Coordination Chemistry ; Volume 66, Issue 3 , 2013 , Pages 464-472 ; 00958972 (ISSN) Amini, M ; Bagherzadeh, M ; Moradi-Shoeili, Z ; Boghaei, D. M ; Ellern, A ; Woo, L. K ; Sharif University of Technology
    A new manganese(III) complex [(N-O)2Mn(OAc)] was synthesized using 2-(2'-hydroxyphenyl)-5,6-dihydro-1,3-oxazine (N-O) as a bidentate O, N donor. The complex has been characterized by elemental analysis, IR, UV-vis spectroscopy, and X-ray structure analysis. Oxidation of sulfides and epoxidation of olefins, respectively, to their corresponding sulfoxides and epoxides were conducted by this catalyst using urea hydrogen peroxide as oxidant at room temperature under air. The catalyst is efficient in oxidation reactions giving high yields and selectivities  

    Immobilized manganese porphyrin on functionalized magnetic nanoparticles via axial ligation: Efficient and recyclable nanocatalyst for oxidation reactions

    , Article Journal of Coordination Chemistry ; Volume 68, Issue 13 , 2015 , Pages 2347-2360 ; 00958972 (ISSN) Bagherzadeh, M ; Mortazavi Manesh, A ; Sharif University of Technology
    Taylor and Francis Ltd  2015
    Magnetic nanoparticles (MNPs), Fe3O4@SiO2, have been prepared and functionalized by 3-(chloropropyl)trimethoxysilane and then by imidazole to synthesize Fe3O4@SiO2-Im. The functionalized Fe3O4 nanoparticles were used as a support to anchor manganese porphyrin via axial ligation. The prepared catalyst was characterized by elemental analysis, FT-IR spectroscopy, X-ray powder diffraction, UV-vis spectroscopy, and scanning electron microscopy. Application of immobilized manganese porphyrin as a heterogeneous catalyst in oxidation of alkenes and sulfides was explored. To find suitable reaction conditions,... 

    Manganese(III) porphyrin anchored onto magnetic nanoparticles via “Click” reaction: An efficient and reusable catalyst for the heterogeneous oxidation of alkenes and sulfides

    , Article Inorganic Chemistry Communications ; Volume 107 , 2019 ; 13877003 (ISSN) Bagherzadeh, M ; Hosseini, M ; Mortazavi Manesh, A ; Sharif University of Technology
    Elsevier B.V  2019
    Oxidation of a variety of organic compounds, using Mn-porphyrin, mesotetrakis(4-hydroxyphenyl)porphyrinatomanganese(III), supported onto functionalized silica-coated magnetic nanoparticles via “Click” reaction has been investigated. The heterogeneous catalyst was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-IR spectroscopy, inductively coupled plasma optical emission spectroscopy (ICP/OES) and energy-dispersive X-ray spectroscopy (EDX). Thermogravimetric analysis (TGA) demonstrated that the prepared catalyst was thermally stable to almost 300 °C, exhibiting high thermostability of the nanocatalyst over a broad range of temperatures. This... 

    Oxidation of benzylic alcohols to carbonyl compounds with hydrogen peroxide catalysed by manganeses chloride supported on montmorillonite K10

    , Article Journal of Chemical Research ; Issue 8 , 2005 , Pages 484-485 ; 03082342 (ISSN) Hashemi, M. M ; Khalili, B ; Eftekhari-sis, B ; Sharif University of Technology
    Scientific Reviews Ltd  2005
    Manganeses(II) chloride supported on montmorillonite K10 was found to be an efficient catalysts for the oxidation of alcohols to carbonyl compounds with hydrogen peroxide as oxidant  

    Epoxidation of terminal olefins by oxygen catalysed by a mixture of manganese and cobalt salts of p-aminobenzoic acid supported on silica gel

    , Article Journal of Chemical Research - Part S ; Issue 10 , 2003 , Pages 662-663 ; 03082342 (ISSN) Hashemi, M. H ; Khoshabro, D. K ; Sharif University of Technology
    Scientific Reviews Ltd  2003
    A mixture of cobalt and manganese salts of p-aminobenzoic acid supported on silica gel catalyses the epoxidation of terminal olefins to the corresponding 1,2-epoxy compounds in the presence of oxygen  

    Self-assembled one-pot synthesis of red luminescent CdS:Mn/Mn(OH)2 nanoparticles

    , Article Journal of Luminescence ; Volume 128, Issue 12 , December , 2008 , Pages 1980-1984 ; 00222313 (ISSN) Marandi, M ; Taghavinia, N ; Iraji Zad, A ; Mahdavi, S. M ; Sharif University of Technology
    We report a novel method of growing red luminescent (635 nm) Mn-doped CdS (CdS:Mn) nanoparticles capped by an inorganic shell of Mn(OH)2. CdSO4, Na2S2O3 and Mn(NO3)2 were used as the precursors, and thioglycerol (C3H8O2S) was employed as the capping agent and also the catalyst of the reaction. Using these materials resulted in very slow rate of the reaction and particles growth. The self-assembled one-pot process was performed at pH of 8 and Mn:Cd ratio of 10, and took about 10 days for completion. CdS:Mn nanoparticles are slowly formed in the first day of the process; however, the luminescence is weak. After 7 days, the solution turns white turbid through the formation of additional... 

    Efficient oxidation of olefins and sulfides catalyzed by manganese(III)-tridentate Schiff base complex using UHP as oxidant

    , Article Catalysis Communications ; Volume 9, Issue 7 , 2008 , Pages 1600-1606 ; 15667367 (ISSN) Bagherzadeh, M ; Tahsini, L ; Latifi, R ; Sharif University of Technology
    Catalytic studies were performed to develop a simple oxidation system for olefins and sulfides using manganese(III)-tridentate Schiff base complex, Mn(N-OPh-sal)(acac)(EtOH) (N-HOPh-Hsal = N-hydroxyphenyl-salicyldienamine, Hacac = acetylacetone), and urea-hydrogen peroxide (UHP) as terminal oxidant. Conversions up to 90% for olefins at 0 °C and 96% for sulfides at room temperature as well as sulfoxide selectivity up to 73% were achieved in short reaction times. Also this study confirms the accelerating effect of strong π-donor axial ligands such as imidazole (ImH) on the oxidation reactions. © 2008 Elsevier B.V. All rights reserved  

    Catalytic activity of manganese(III)-oxazoline complexes in urea hydrogen peroxide epoxidation of olefins: The effect of axial ligands

    , Article Journal of Molecular Catalysis A: Chemical ; Volume 260, Issue 1-2 , 2006 , Pages 163-169 ; 13811169 (ISSN) Bagherzadeh, M ; Latifi, R ; Tahsini, L ; Sharif University of Technology
    The catalytic activity of two manganese(III)-oxazoline complexes [Mn(phox)2(CH3OH)2]ClO4 and Mn(phox)3 (Hphox = 2-(2′-hydroxylphenyl)oxazoline), was studied in the epoxidation of various olefins. All of epoxidation reactions were carried out in (1:1) mixture of methanol:dichloromethane at room temperature using urea hydrogen peroxide (UHP) as oxidant and imidazole as co-catalyst. The epoxide yields clearly demonstrate the influence of steric and electronic properties of olefins, the catalysts and nitrogenous bases as axial ligand. [Mn(phox)2(CH3OH)2]ClO4 catalyst with low steric properties has higher catalytic activity than Mn(phox)3. The highest epoxide yield (95%) was achieved for indene... 

    Solution structure of a seven coordinated manganese(II) complex via electrospray ionization mass spectrometry

    , Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 75, Issue 3 , 2010 , Pages 1168-1170 ; 13861425 (ISSN) Najafpour, M. M ; Boghaei, D. M ; Sjöberg, P. J. R ; Sharif University of Technology
    The mononuclear complex [Mn(tptz)(CH3COO)(OH2)2]NO3 (1) was investigated by electrospray ionization mass spectrometry in aqueous solution at pH 4.5. Electrospray ionization mass spectrometry shows that mononuclear and dinuclear manganese cationic species are present in solution, probably in equilibrium with neutral 1. An experiment showed that the most important reaction in the presence of oxone (2KHSO5·KHSO4·K2SO4) is decoordination  

    Activated layered manganese oxides with deposited nano-sized gold or silver as an efficient catalyst for epoxidation of olefins

    , Article RSC Advances ; Volume 3, Issue 46 , 2013 , Pages 24069-24074 ; ISSN: 20462069 Najafpour, M. M ; Amini, M ; Sedigh, D. J ; Rahimi, F ; Bagherzadeh, M ; Sharif University of Technology
    Activated layered manganese oxides with deposited nano-sized gold or silver were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrometry, atomic absorption spectroscopy and energy-dispersive X-ray mapping. Here, we report that Au or Ag nanoparticles deposited on layered Mn oxides improve the catalytic activity of the Mn oxides toward the epoxidation of olefins in the presence of H2O2 and NaHCO3  

    A very simple method to synthesize nano-sized manganese oxide: An efficient catalyst for water oxidation and epoxidation of olefins

    , Article Dalton Transactions ; Volume 41, Issue 36 , Jul , 2012 , Pages 11026-11031 ; 14779226 (ISSN) Najafpour, M. M ; Rahimi, F ; Amini, M ; Nayeri, S ; Bagherzadeh, M ; Sharif University of Technology
    RSC  2012
    Nano-sized particles of manganese oxides have been prepared by a very simple and cheap process using a decomposing aqueous solution of manganese nitrate at 100 °C. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction spectrometry have been used to characterize the phase and the morphology of the manganese oxide. The nano-sized manganese oxide shows efficient catalytic activity toward water oxidation and the epoxidation of olefins in the presence of cerium(iv) ammonium nitrate and hydrogen peroxide, respectively  

    Heterogeneous water oxidation by bidentate schiff base manganese complexes in the presence of cerium(IV) ammonium nitrate

    , Article Transition Metal Chemistry ; Volume 34, Issue 4 , 2009 , Pages 367-372 ; 03404285 (ISSN) Najafpour, M. M ; Boghaei, D. M ; Sharif University of Technology
    Oxygen evolution was observed upon mixing solid manganese(III) bidentate Schiff base complexes with aqueous solutions of cerium(IV) ammonium nitrate. However, oxygen evolution was not observed upon mixing solutions of the complexes (in acetonitrile) with Ce(IV). Electron-withdrawing substituents on the Schiff base ligands (NO2, Br) enhanced the reactivity of the manganese complexes toward oxygen evolution. Oxygen evolution was also affected by R groups on the ligands, in the order Me > Et Bz. © 2009 Springer Science+Business Media B.V  

    Effects of stabilizers on sustainability, activity and decolorization performance of Manganese Peroxidase enzyme produced by Phanerochaete chrysosporium

    , Article Journal of Environmental Chemical Engineering ; Volume 8, Issue 6 , 2020 Emami, E ; Zolfaghari, P ; Golizadeh, M ; Karimi, A ; Lau, A ; Ghiasi, B ; Ansari, Z ; Sharif University of Technology
    Elsevier Ltd  2020
    Manganese Peroxidase (MnP), is one of the most promising lignin depolymerization enzymes, which has been widely used for degradation purposes. Nevertheless, MnP tends to lose activity rapidly during its maintenance phase and degradation process, especially in the inevitable presence of hydrogen peroxide. This study aimed to improve MnP efficiency produced by Phanerochaete chrysosporium, via enhancing its sustainability. In this context, the effects of MnO2, Fe3O4, PEG, Veratryl Alcohol (VA), and DMSO as stabilizing agents on MnP activity were explored both in vivo and in vitro. During in vivo experiments, heterogeneous Fe3O4 was found to be the desirable choice to enhance MnP production,... 

    Model Systems for Oxygen – Evolving Complex in Photosystem II: Manganese Oxides and Manganese Complexes with O and N Donor Ligands

    , Ph.D. Dissertation Sharif University of Technology Najafpour, Mohammad Mahdi (Author) ; Mohammadi Boghaei, Davar (Supervisor)
    The aim of this study is to mimic water oxidizing complex to find new materials and also to understand their rules in this matter. To achieve this, manganese complexes containing 2,4,6-tris (2-pyridyl)-1,3,5-Triazine, 1,10-phenanthroline, 1,10-bipyridine, Schiff base, amino acids, 2,6-pyridinedicarboxylic acid, 2-pyridinecarboxylic acid have been synthesized and characterized by elemental analysis, IR, EPR, ESI-MS, electronic absorption spectroscopy, electrochemistry, X-ray diffraction and oxygen evolution in presence of oxone and Ce(IV). It is shown that the reaction between Mn(II) complexes containing 2,4,6-tris¬(2-pyridyl)-1,3,5-Triazine, 1,10-phenanthroline, 1,10-bipyridine,...