Sharif Digital Repository

Current study reports a state-of-the-art approach for synthesis of nanocatalyst based on Oxo-vanadium Schiff base complex which itself is, covalently, immobilized on core-shell magnetic nanoparticles of silica-modified magnetite (Fe3O4@SiO2) and the substantial potential it offers as heterogeneous catalyst in selective oxidation of sulfides.Synthesized materials and complexes in this project were characterized by means of modern spectral devices such as FT-IR, XRD and SEM.Unlike routine process of the preparation of heterogeneous catalysts that requires further modification of the core-shell nanoparticles with capping agents, here we have been capable of cutting some time-consuming steps... 

In this study polyoxotungstate-based inorganic-organic hybrid [C272H162N80Cu16.5W36O129Na9] .80.5H2O was synthesized in situ. This inorganic-organic hybrid resulted from the reaction between copper salt and sodium tungstate with the benzimidazole ligand. Combining inorganic-organic hybrid with polyoxotungstate improved the ability of this catalytic system in oxidation and cycloaddition reactions. The resulting product was identified by IR, X-ray diffraction (XRD), elemental analysis (CHNS), inductively coupled plasma (ICP-OES), field emission scanning electron microscope (FE-SEM) and EDX were technique. The catalyst was used in optimal conditions in sulfide oxidation and azide-alkyne... 

In this project, a new magnetically recoverable nanocatalyst was developed by immobilizing of vanadyl acetylacetonate, [VO(acac)2], onto surface of silica coated magnetite nanoparticlest that modified by reaction between 3-aminopropylthriethoxy silane and 5-bromosalicylaldehyde. In the first step, magnetite cores were synthesized by co-precipitation method and coated by tetraethyl orthosilicate (TEOS) and modified by 3-aminopropyltriethoxy silane to provide a precursor for Schiff base condensation reaction. In the next step, amino-functionalized silica coated magnetite nanoparticles were reacted by 5-bromosalicylaldehyde to formation a Schiff base moiety onto surface of magnetite coated... 

The goal of this study is to synthesise and study the catalytic properties of a Mn-Porphyrin complex fixed on a magnetic nanoparticle bed. This nanocatalyst was used in oxidation of sulfides and epoxylation of olefin. In the multistage synthesis of this catalyst, iron oxide magnetic nanoparticles were first prepared, then, by silanizing these nanoparticles, and then using the 3-chloropropyltrimethoxy methanol reactor, Immobilzation the material on the substrate and immediately react in reaction Substitution of the nucleus of friendship and using a sodium azide reaction, bromide is replaced by azide. Subsequently, by synthesising 4-hydroxy porphyrin and replacing one of its positions with... 

In this thesis, functionalized Fe3O4 nanoparticles have been utilized as a support for immobilization of homogeneous catalysts. The catalytic activity of the supported heterogeneous nanocatalysts was investigated in hydrocarbon and sulfide oxidation reactions. In the first part of this research, imidazole functionalized Fe3O4 nanoparticles (Fe3O4@SiO2-Im) were used as a support to anchor manganese porphyrin complex, [MnT(4-OMeP)P]OAc; via axial ligation. Catalytic application of the immobilized manganese porphyrin was studied in oxidation of alkenes and sulfides. To find suitable reaction conditions, the effect of different parameters such as solvent and temperature on immobilization process... 

In this study a novel oxo-diperoxo tungsten(VI) complex [WO(O2)2(phox)] was prepared by reaction of WO3 in H2O2 with oxazine-type ligand, 2-(2′-hydroxyphenyl)-5,6-dihydro-1,3-oxazine (Hphox). The complex was characterized by FTIR, 1H NMR and elemental analysis. The single-crystal X-ray diffraction studies revealed a seven coordinate tungsten center with a distorted octahedral geometry. The [WO(O2)2(phox)] complex was applied as a catalyst in efficient, and selective oxidation of sulfide to sulfoxide using 30% H2O2 or UHP as oxidants. This catalyst showed excellent catalytic activities and high selectivities in producing a variety of aryl and alkyl sulfoxides under mild conditions. To get... 

In order to have more understanding of the cooperative effect between the metal centers in the multimetallic complexes, on their physicochemical properties and chemical reactivity, some new bi- and tetra-nuclear Cu(II), Ni(II) and Pd(II) complexes of compartmental binucleating ligands were synthesized and characterized. In this study, a series of new compartmental binucleating thiophenol-based proligands PL1-PL4 from the Schiff base condensation of 2 equiv. of o-aminophenol or 2-amino-4-methylphenol with 1 equiv. of 2,6-diformyl-4-alkyl- thiocarbamoyl were synthesized and characterized. New Bi- and tetra-nuclear copper (II) complexes derived from these binucleating compartmental... 

In this project a new dioxovanadium (V) complex of Schiff base ligand N`-[1-(2-hydroxynaphthyl)methylene]-2-hydroxy benzohydrazide was synthesized and fully characterized. This complex is a pentacoordinate one in which the dioxo groups are in cis form. For synthesis of this complex, first, the intermediate compound 2-hydroxy benzohydrazide was synthesized from hydrazine and methyl salicylate and condensed with 2-hydroxynaphthaldehyde to give the Schiff base ligand (H2NBD). Then from reaction of ligand and ammonium vanadate in DMF in 65 ̊C, the NH4[VO2(NBD)] was prepared. This complex was fully characterized by UV, NMR and IR spectroscopies and it’s application as catalyst in sulfoxidation... 

We have reported a new and efficient synthesis of tetrahydrothiopyrano [2,3-b]indole skeletons via unique tandem reaction of indoline-2-thiones to Baylis-Hillman adduct acetates. This protocol is a very mild and simple method for construction heterocycles in a one-step process. This is a convenient and diastereoselective synthesis of methyl 4-aryl-2,3,4,9-tetrahydrothiopyrano[2,3-b]indole-3-carboxylate systems in the presence of K2CO3 in acetonitrile. The major benefits of the current study are the one-pot procedure, high yields and diastereoselectivity, short reaction times and the similarity of the products to the biologically active moieties.
In addition 1, 4-diazabicyclo [2.2.2]... 

In this project synthesis and characterization of a novel dioxomolybdenum(VI), with tetradentates Schiff base ligand which was soluble in water. The first step of complex synthesis was chloromethylation of salicylaldehyde and the second step was the reaction with the pyridine. After that salen ligand will be synthesized by reaction with ethylene diamine. In the presence of Mo(acac)₂(VI) the final product will be synthesized. The complex was characterized by spectroscopic methods such as UV, NMR, FT-IR and CHN. The synthetized complex was studied for olefin (aliphatic and aromatic) epoxidation as well as sulfide oxidation. It was more active in aliphatic olefins epoxidation than sulfide... 

In this work, synthesized Fe3O4 magnetic nanoparticles andcoated with SiO2 to prepare magnetic core-shell nanoparticles. Then immobilized Schiff baseof iron and vanadium complexes on magnetic core-shell nanoparticles was prepared as a recoverable magnetic nano catalysts. These catalysts were named Fe3O4@SiO2@L1@Fe, Fe3O4@SiO2@L2@Fe and Fe3O4@SiO2@L3@V. Furthermore,olefines epoxidation, sulfides and alcohols oxidation were studied with using iron and vanadium magnetic nano catalysts. The supported catalysts were characterized by atomic absorption, FT-IR and UV–Vis spectra.The catalytic performance of the synthesized iron catalyst was tested for the epoxidation of cyclohexene, styrene and... 

To synthesizeFe3O4@SiO2 core-shellnanoparticles,at first,Fe3O4 magnetic nanoparticle synthesisedby usingcoprecipitation method.Then tetraethyl orthosilicate (TEOS) was used to coverthe surface of this nanoparticle with layer of silica. In the next step, the surface of Fe3O4@SiO2 core-shellnanoparticlesfunctionalized by NO-bidentate and ONO-tridentate ligands. Finally the functionalized nanoparticle coordinated to oxovanadium(IV) to achieve Fe3O4@SiO2@NO-VO2+ and Fe3O4@SiO2@ONO-VO2+nanocatalysts for selective oxidation of sulfides to corresponding sulfoxide and oxidation of alkene. FT-IR, 1HNMR, 13CNMR, SEM, VSM and ICP analysis were used for characterization of this nanocatalysts. This... 

In nature, catalysis is of vital importance in a wide variety of biochemical processes catalyzed by metalloenzymes. The functions performed by the metalloenzymes and their significance have inspired a range of biomimetic studies, and intense efforts have been concentrated on the synthesis of low molecular weight complexes to model the spectroscopic features of such enzymes. Concomitantly, a challenging frontier in the field of biomimetic chemistry is the development of highly reactive model compounds that are able to effect rapid and selective substrate conversion. Some important catalytic transformations that have gained attention in recent years involve the carbon-carbon coupling, olefin...