Search for: platinum
0.007 seconds
Total 132 records

    Synthesis and Characterization of New Bis(N-heterocyclic) Carbene Platinum (II) Complexes: Study of Stability and Reactivity in C-H Activation

    , M.Sc. Thesis Sharif University of Technology Hoseinmardi, Sussan (Author) ; Jamali, Sirous (Supervisor)
    Preparation of two new Bis-N-heterocyclic carbene (Bis-NHC) platinum (ІІ) complexes have been described. The reaction of the Bis-NHC complex [PtMe2(Bis-NHC)], 1, in which Bis-NHC = 1,1’-methylene-3,3’-di(tert-Bu)imidazole ylidene, with two equivalent trifluoroacetic acid give the new Bis-NHC platinum [Pt(Bis-NHC)(CF3COO)2], 2. Complex 2 has been characterized by multinuclear NMR spectroscopy in solution and its solid state structure determined using X-ray crystallography. The mono-methyl Bis-NHC platinum(ІІ) complex, {PtMe(Bis-NHC)[OHB(C6F5)3]}, 3, has been prepared by the reaction of one equivalent B(C6F5)3 with [PtMe2(Bis-NHC)], 1. The mono-methyl complex 1 has a labile ligand... 

    Metal-Organic cubane cage with trimethylplatinum(Iv) vertices

    , Article Inorganic Chemistry ; 2021 ; 00201669 (ISSN) Hendi, Z ; Jamali, S ; Mahmoudi, S ; Samouei, H ; Nayeri, S ; Chabok, S. M. J ; Jamshidi, Z ; Sharif University of Technology
    American Chemical Society  2021
    Herein we describe the synthesis and characterization of the first platinum(IV) metal-organic cage [(Me3PtIV)8(byp)12](OTf)8 (2), in which the organometallic moieties trimethylplatinum(IV) (PtMe3) occupied the corners of a cubane structure and 4,4′-bipyridine ligands used as linkers. The first-principles density functional theory calculations showed that the highest occupied molecular orbitals were localized on the PtMe3 moieties, while the lowest unoccupied molecular orbitals were distributed on the organic linkers. © 2021 American Chemical Society  

    Removal of heavy metals from aqueous solution using platinum nanopartcles/Zeolite-4A

    , Article Journal of Environmental Health Science and Engineering ; Vol. 12, issue. 1 , 2014 ; ISSN: 2052336X Mehdizadeh, S ; Sadjadi, S ; Ahmadi, S. J ; Outokesh, M ; Sharif University of Technology
    The effects of varying operating conditions on metals removal from aqueous solution using a novel platinum nanopartcles/Zeolite-4A adsorbent are reported in this paper. Characterization of the adsorbent showed successful production of platinum nanopartcles on Zeolite-4A using 3 Wt% platinum. The effects of operation conditions on metals removal using this adsorbent were investigated. The optimal metals adsorption was observed at pH 7, 0.1 g/10 mL dosage and 30 min contact time. Sorption data have been interpreted in terms of Langmuir and Freundlich isotherms  

    Electrodeposition of Platinum Nanowires

    , M.Sc. Thesis Sharif University of Technology Hashemi Darian, Sahar (Author) ; Dolati, Abolghasem (Supervisor) ; Ghorbani, Mohammad (Supervisor)
    Platinum nanowires were prepared by electrodeposition in polycarbonate membrane, with different average diameter of nanowires about 15, 50 and 100 nm and the height about 6 µm. Kinetics of electrodeposition process were studied by electrochemical techniques such as voltammetry and chronoamperometry methods. Diffusion coefficient was then calculated from the electrochemical parameters and consequently the density of primer nuclei was extracted. The morphology of Pt nanowires was characterized by SEM, TEM and EDX. The results show that growing Nanowires on the surface of template is branch-like. The electro-oxidation of methanol and hydrogen on this electrode is investigated at room... 

    Synthesis of Platinum Nanoparticles and Study on its Application as a Catalyst and an Adsorbent of the Radioactive Elements

    , M.Sc. Thesis Sharif University of Technology Mehdizadeh, Sofia (Author) ; Outokesh, Mohammad (Supervisor) ; Ahmadi, Javad (Supervisor) ; Sadjadi, Sodeh (Co-Advisor)
    The present study was aimed at investigating the use of platinum and platinum nanoparticles stabilized on zeolite as catalyst for the reduction reaction of p-nitrotoluene as one of the dangerous pollutants. The adsorption properties of platinum based on zeolite have been studied for some heavy metals. Monodispersed platinum nanoparticles were synthesized through reduction of H2PtCl6 by ethanol in the presence of polyvinyl pyrrolidone (PVP) as a stabilizer, and then were immobilized on four types of zeolites. The study then focused on elaboration of the catalytic activity of the nano catalysts under different operational conditions. In order to investigate the catalytic properties, operating... 

    Synthesis and Characterization of Heterobinuclear Cyclometalated Complexes Containing Small Bite Angle Bridging Ligand

    , M.Sc. Thesis Sharif University of Technology Ghazfar, Reza (Author) ; Jamali, Sirous (Supervisor)
    The heteronuclear complexes [MePt(bhq)(μ-dppy)Au(PPh3)]PF6, 2, [MePt(bhq)(dppy)Tl]PF6, 3 and [Me2Pt2(bhq)2(dppy)2Tl]PF6, 4 in which bhq=benzo{h}quinoline and dppy=2-diphenylphosphinopyridine, were prepared by reaction of the mononuclear complex [MePt(bhq)(dppy)] 1 with 1 equivAuCl(PPh3), 1equiv TlPF6 and 1/2 equiv TlPF6 respectively. All the complexes were fully characterized using multinuclear NMR spectroscopy and ESI-MS spectrometry. In addition molecular structures of complexes 2 and 3 in solid state have been determined by X-ray crystallography that shown strong dative bonds between platinum and gold or thallium atoms. As shown by ESI-MS spectrometry, the Pt-Au bond in complex 2... 

    Rapid, efficient and selective reduction of aromatic nitro compounds with hydrazine hydrate in the presence of the plain and supported platinum nanoparticles as catalysts

    , Article Journal of the Iranian Chemical Society ; Vol. 11, issue. 6 , 2014 , pp. 1587-1592 ; ISSN: 1735207X Mehdizadeh, S ; Ahmadi, S. J ; Sadjadi, S ; Outokesh, M ; Sharif University of Technology
    The current study aimed at application of the plain and supported platinum nanoparticles as a heterogenous catalyst for the reduction of aromatic nitro compounds. Monodispersed platinum nanoparticles were synthesized by reduction of H2PtCl6 by ethanol in the presence of polyvinyl pyrrolidone as a stabilizer, and then were immobilized on four types of zeolites. The obtained catalyst granules were characterized by X-ray diffractometry and transmission electron microscopy. The study then focused on elaboration of the catalytic activity of the nano catalysts under different operational conditions. It was found that reaction is adequately rapid at ambient temperature, and by utilizing a... 

    Cycloplatinated(II) complexes containing bridging bis(diphenylphosphino)acetylene: Photophysical study

    , Article Journal of Luminescence ; Volume 179 , 2016 , Pages 222-229 ; 00222313 (ISSN) Jamshidi, M ; Nabavizadeh, S. M ; Sepehrpour, H ; Niroomand Hosseini, F ; Kia, R ; Rashidi, M ; Sharif University of Technology
    Elsevier  2016
    Reaction of the known cycloplatinated (II) complexes [PtAr(C^N)(SMe2)], in which Ar=p–MeC6H4 or p–MeOC6H4 and C^N= 2-phenylpyridinate (ppy) or benzo[h]quinolinate (bhq), with 0.5 equivalent of the bidentate phosphine ligand 1,1′–bis(diphenylphosphino)acetylene, dppac, in acetone at room temperature gave the symmetrical binuclear cycloplatinated(II) complexes [Pt2Ar2(C^N)2(μ–dppac)], 1–4, in which dppac acts as a bridging bidentate ligand. All the complexes were fully characterized using multinuclear (1H, 31P and 195Pt) NMR spectroscopy and the complex [Pt2(p–MeC6H4)2(ppy)2(μ–dppac)], 1, was further identified by single crystal X-ray structure determination. Additional information about the... 

    Factors affecting platinum extraction from used reforming catalysts in iodine solutions at temperatures up to 95 °C

    , Article Hydrometallurgy ; Volume 97, Issue 1-2 , 2009 , Pages 119-125 ; 0304386X (ISSN) Zanjani, A ; Baghalha, M ; Sharif University of Technology
    Platinum extraction from the spent reforming catalysts in iodine-iodide solutions at temperatures from 25 to 95 °C was investigated. The reforming catalyst mostly consists of a porous gamma alumina support with metallic platinum finely dispersed on the walls of the nano-pores of the catalyst support. The effect of a variety of factors, including catalyst particle size, impeller agitation speed, reactant concentrations, liquid to solid mass ratio, temperature and the solution pH on the Pt extraction rate and recovery were investigated. It was found that the catalyst particle sizes less than 106 μm and impeller agitation speed higher than 700 rpm eliminated the effects of catalyst size and... 

    Synthesis, and Characterization of Binuclear Platinum (IV)with Coinage Metals

    , M.Sc. Thesis Sharif University of Technology Abbasi Kamran, Ehsan (Author) ; Jamali, Sirous (Supervisor)
    In this research binuclear platinum(IV) complexes with coinage metals have been synthesized and characterized. the trimethyl platinum(IV) complex [PtMe3(phthalazine)3]+X- has been prepared by the reaction of [PtMe3(THF)]4 with 3 equiv. phthalazine and used as initial material. The first complex, [PtMe3(µ-(phthalazine)2Cl)PtMe3], synthesized via reaction of 2 equiv. [Pt(Me)3(Phthalazine)3] with 1 equiv. [AuClSMe2]. The second complex, [PtMe3(µ-phthalazine)3Ag][BF4], synthesized by reaction of one equiv. of each compound [Ag(CH3CN)4]BF4 and [Pt(Me)3(Phthalazine)3] And the third complex, [PtMe3(µ-phthalazine)3Cu][PF6], synthesized like second one via reaction of [Cu(CH3CN)4]PF6 and... 

    Modeling of platinum extraction from used reforming catalyst in iodine solutions

    , Article ECS Transactions ; Volume 41, Issue 17 , 2012 , Pages 45-51 ; 19385862 (ISSN) ; 9781607683070 (ISBN) Moghaddam, H. R ; Baghallha, M ; Sharif University of Technology
    Platinum extraction from spent reforming catalysts in iodine solutions under atmospheric pressure and at temperatures up to 95°C was previously investigated in our group. In this system, platinum is oxidized from the spent catalyst with tri-iodide. In some of the experiments, it was observed that platinum extraction peaked and then decreased. This indicates that a precipitation reaction slowly occurs that removes the dissolved Pt ions from the solution. Power-law rate equation for the Pt extraction to PtI6 2- and the precipitation of the dissolved platinum to PtI 4(s) was implemented to model the experimental Pt extraction data. The activation energies for the platinum dissolution reaction... 

    Platinum extraction from spent catalysts by TOPO utilizing RSM technique

    , Article Advanced Materials Research ; Volume 548 , 2012 , Pages 186-192 ; 10226680 (ISSN) ; 9783037854532 (ISBN) Nejad, H. H ; Kazemeini, M ; Fattahi, M ; Sharif University of Technology
    In this research, data on liquid-liquid extraction of platinum from commercial spent catalysts by trioctylphosphine oxide (TOPO) in toluene were experimentally obtained. Alkaline metal salts were used to optimize the separation process. Best Salting-out effect was obtained by KCl which extracted up to 90% of platinum utilizing TOPO. Furthermore, extraction percentages of Pt and Al depending upon different factors were investigated. It was observed that the extraction process was kinetically fast and achieving the equilibrium time took less than 30 seconds. Optimized points obtained utilizing response surface methodology (RSM) by the "Design Expert" software in order to minimize the... 

    Organoplatinum(ii) complexes containing chelating or bridging bis(N-heterocyclic carbene) ligands: Formation of a platinum(ii) carbonate complex by aerial CO2 fixation

    , Article Dalton Transactions ; Volume 40, Issue 37 , Jun , 2011 , Pages 9362-9365 ; 14779226 (ISSN) Jamali, S ; Milić, D ; Kia, R ; Mazloomi, Z ; Abdolahi, H ; Sharif University of Technology
    The preparation of two new bis(N-heterocyclic carbene) platinum(ii) complexes, in which NHC rings are joined by a CH2 linker group, is described. While, the chelate complex [PtMe2(bis-NHC1)], 1, was formed with large tert-butyl wingtips, the iso-propyl N-substituent analogue favors formation of the cluster complex [Pt2Me4(μ- SMe2)(μ-bis-NHC2)]2(μ-Ag2Br2), 2, in which two binuclear platinum(ii) complexes are linked together by an Ag2Br2 unit. The chelating platinum complex 1 undergoes aerial CO2 fixation and forms platinum(ii) carbonate complex [Pt(CO3)(bis-NHC1)], 3  

    Electrodeposition of platinum nanowires: Electrochemical characterization

    , Article ECS Transactions, 25 April 2010 through 30 April 2010 ; Volume 28, Issue 18 , April , 2010 , Pages 25-35 ; 19385862 (ISSN) ; 9781607681946 (ISBN) Mahshid, S. S ; Dolati, A ; Hashemi Daryan, S ; Ghorbani, M ; Ghahramaninezhad, A ; Physical and Analytical Electrochemistry ; Sharif University of Technology
    Platinum nanowires (PtNWs) were electrodeposited on the polycarbonate templates (PCTs) in aqueous solution of H2PtCl6 in triply distilled water. Nanowires with diameters of 50 and 100 nanometers were electrodeposited on the same condition. The kinetics of electrodeposition process was studied by electrochemical techniques such as voltammetry and chronoamperometry methods. Increasing the scan rate, the peaks shifted to more negative potentials and the current density also increased in each peak which was typical for a diffusion-control process. The potential range for the deposition of platinum nanowires was specified and consequently the potentiostatic i-t transients were utilized to produce... 

    Synthesis and Activity Test of Dehydrogenation Catalyst for C10-C14 Paraffin

    , M.Sc. Thesis Sharif University of Technology Mamanpoush, Mahdi (Author) ; Baghghalha, Morteza (Supervisor)
    Dehydrogenation of C10-C14 normal paraffins on Pt/alumina catalyst is a reaction of prime importance particularly to the detergent industry for the manufacture of the active ingredients. In this thesis, the modifying effect of Zn, Li, K, and Mg on the activity and selectivity of the Pt-Sn/γ-Al2O3 dehydrogenation catalysts were investigated. The catalysts were prepared by co-impregnation, characterized by TPR, BET, SEM, EDAX and XRD techniques and tested in a tubular reactor. Zinc reduced the activity of Pt-Sn alloy and hence reduced the catalyst activity in the dehydrogenation reaction and enhanced its selectivity to normal mono olefins. The addition of Li, K, and Mg to Pt-Sn/γ-Al2O3... 

    Synthesis and Characterization of Cyclometalated Platinum Complexes Containing 2-Vinylpyridine Ligand

    , M.Sc. Thesis Sharif University of Technology Kamyar Khaledi, Niloufar (Author) ; Jamali, Sirous (Supervisor)
    The cyclometalated platinum(II) complex [Pt(Me)(bhq)(2-vpy)], 2, in which bhq = benzo{h}quinolone, 2-vpy = 2-vinylpyridine, has been prepared by reaction of the cyclometalated complex [Pt(Me) bhq)(SMe2)], 1 with one equiv 2-vinylpyridine. The similar complex [Pt(p-tolyl)(ppy)(2-vpy)], 3 in which ppy = 2-phenyl pyridine, has been prepared from reaction of the platinum(II) complex cis-[Pt(p-MeC6H4)2(SMe2)2] with one equiv 2-phenylpyridine and one equiv 2-vinylpyridine. Reaction of 2 with one equiv Br2 in acetone gave the cyclometalated platinum(IV) complex [Pt(bhq)Me(Br)(NC5H4CHCH2Br)], 4. The structure of the complexes 1-3 were determined using NMR Spectroscopy. The crystal structure of 3... 

    The Use of Non-platinum Electro-catalyst for Low Temperature Fuel Cells

    , M.Sc. Thesis Sharif University of Technology Hamzehie, Mohammad Ehsan (Author) ; Samiee, Leila (Supervisor) ; Seifkordi, Ali Akbar (Co-Advisor)
    In the recent decades, Polymer Electrolyte Membrane Fuel Cells (PEFC) have been known as an appropriate type of fuel cells, due to being electrochemical converter and clean energy generator with high power density and having low operation temperature and launch time. Palatine is one of the major materials that are used in electro-catalysts of fuel cell. Due to shortage of palatine resources and its high price, fuel cell production is not economical. To achieve economic conditions for production of fuel cell, two major methods are proposed:
    1) Reduction of the employed amount of palatine in electro-catalyst
    2) Full replacement of palatine with cheap materials
    In the current... 

    Electrodepositon of Platinum Nanotubes

    , M.Sc. Thesis Sharif University of Technology Yousefi, Elahe (Author) ; Dolati, Abolghasem (Supervisor)
    Platinum nanotubes were deposited inside the pores of polycarbonate template with the pore size of 200 nm by electrochemical methods. In this regard a solution containing of 0.05 M H2PtCl6 and 0. 1 M H2SO4 in doubly distilled water was utilized. The electrodeposition process was studied by electrochemical techniques such as voltammetry and chronoamperometry methods. It was observed that the process was conducted in several stages including; nucleation and growth in steady state regime. Furthermore, it was concluded that electrodeposition was affected by mass transport restriction and was controlled by a diffusion process. In this regard, all the voltammograms were shifted to more negative... 

    Kinetics of chemical ordering in a Ag-Pt nanoalloy particle via first-principles simulations

    , Article Journal of Chemical Physics ; Volume 137, Issue 19 , 2012 ; 00219606 (ISSN) Negreiros, F. R ; Taherkhani, F ; Parsafar, G ; Caro, A ; Fortunelli, A ; Sharif University of Technology
    The energetics and kinetic energy barriers of vacancy/atom exchange in a 37-atom truncated octahedron Ag-Pt binary cluster in the Ag-rich range of compositions are investigated via a first-principles atomistic approach. The energy of the local minima obtained considering various distributions of a single vacancy and a few Pt atoms within the cluster and the energy barriers connecting them are evaluated using accurate density-functional calculations. The effects of the simultaneous presence of a vacancy and Pt atoms are found to be simply additive when their distances are larger than first-neighbors, whereas when they can be stabilizing at low Pt content due to the release of strain by the... 

    A comparative study of the electrooxidation of ethylene glycol on transition metal electrodes in alkaline solution

    , Article Journal of New Materials for Electrochemical Systems ; Volume 15, Issue 4 , 2012 , Pages 255-263 ; 14802422 (ISSN) Danaee, I ; Jafarian, M ; Shahnazi Sangachin, A. A ; Gobal, F ; Sharif University of Technology
    Electrodes made of group VIII and IB metals were examined for their redox process and electrocatalytic activities towards the oxidation of ethylene glycol in alkaline solutions. The method of cyclic voltammetery (CV) and Open circuit potentials measurement (OCP) was employed. It is found that considerable electrooxidation current are observed for silver and copper but lower anodic overpotential for oxidation is obtained for gold and platinum. Oxide layer produced on the surface of all electrodes in alkaline solution under anodic scan participates in ethylene glycol electrooxidation. Oxidation current observed in the reverse scans for platinum and gold are higher than those observed in...