Sharif Digital Repository

Briefly in this thesis, these subjects have been investigated: In recent years, water is used as a solvent instead of an organic solvents have become more and more important due to cheap and environmental consideration. In this context, preparation of quinoxaline, pyrrole, new 1,4-dihydropyridine and reduction of imine to amine with 1,4-dihydropyridine derivatives as the reducing agents with the use of one-pot multicomponent reaction have been reported. The existence of several hydrogen bonding groups (NH) in the new dihydropyridines they acts as biologically active compounds in the forthcoming years. In continuation, oxidation of thiols to disulfides in the presence of NBS and NCS and... 

In this thesis, heterogenous catalysts based on magnetic nanoparticles were synthesized. In these catalysts, magnetic nanoparticles were coated with defferent fuctional groups to produce a catalyst with magnetic properties which is easily separated from the reaction medium. The structure of synthesized catalyst was characterized using techniques such as transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and CHNS elemental analysis. Easy preparation, low cost, biodegradability and high thermal stability are advantages of these catalysts. At the end, the catalytic properties of resulted catalysts were investigated in many... 

The purpose of this study is to prepare a catalyst for copper nanoparticles that can be used in C-H activation processes in order to increase copper salt catalytic processes by converting it into a catalyst with characteristics of having recovery cycles, convenient separation and environmental friendliness and being in nano size. Consequently, copper nanoparticles are directly grafted onto graphene oxide, or using para-aminobenzoic acid grafted on graphene oxide. A copper nanoparticle catalyst was used in the reaction to activate the C(sp2)-H bonds of benzoxazole molecule and C-N bonds formation with secendary amines. Using the results of transition electron microscopy (TEM), scanning... 

The current thesis deals with designing of functionalized nanoporous catalysts modified with organic groups and ionic liquids and their applications for some challenging organic reactions such as synthesis of adipic acid and fatty acid esterifications. In this condition the catalysts show enhanced activity since the hydrophobicity of the surface can tune by applying organic groups. In this regard, oxidation of cyclohexene was performed using hydrogen peroxide as oxidant in the present of tungstate based task–specific ionic liquids and silica–functionalized ammonium tungstate as green catalysts. The results indicate that adipic acid achieves in high yield with excellent selectivity.... 

In this thesis the graphene-based magnetic nanocatalyst was synthesized. The surface of this catalyst was cavered by silica and AgNPs. In addithion of simple sepration by magnetbar, yeild of reaction was promoted by surface modification. Catalyst structure was verified by transmission electron microscopy , scanning electron microscope, fourier transform infrared spectroscopy, X-ray diffraction and Energy dispersive spectroscopy.At the end catalytic activity was examined by oxidation reaction in persense of different alcohols. The oxidation of benzylic alcohol with electron withdrawing substituents was more difficult and the yield was lower, but electron donor substituents effect positively... 

In this thesis, a heterogeneous nanocatalyst based on graphene oxide was synthesized. To improve the graphene oxide, it was reacted with paraaminobenzoic acid and then metal salts (cobalt and manganese) were coated on it. The structure of the catalyst was confirmed by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), quantitative X-ray diffraction (EDS) and infrared (FT-IR) spectroscopy. Finally, the catalytic properties of the catalysts were evaluated in the oxidation reaction of different alcohols in the presence of oxygen. In the presence of benzyl alcohols with lethal electron groups, the oxidation conditions are stricter and the reaction efficiency is lower.... 

The purpose of this study is to prepare platinum nanoparticles catalysts whitch can be used to C-H activation processes. In order to increase platinum salt catalytic activity, by converting it into a catalyst with characteristics of having recovery cycles, convenient separation and environmental friendliness and being in nano size. Consequently, platinum nano particles were grafted on modified graphene oxides. Catalysts structures were verified by scanning electron microscope, fourier transform infrared spectroscopy, X-ray diffraction, and energy dispersive spectroscopy. Subsequently catalytic activity was examined for C(sp3)-H activation reaction with 3 amines and C-C bond formation. A... 

This thesis is divided into two parts: In part I, which is theoretical part, we were looking for a computational method which is extensively comparable with experimental results to determine pKa of wide variety of organic compounds. The pKa is an important property in many sciences such as chemistry, biology, and material science, since inclination of a compound to donate or accept a proton is fundamental to understanding many chemical and biochemical processes. Experimentally determined pKa values are not always available from literature sources and often estimated values are employed in their place. It is useful, therefore, to have reliable and accurate means of calculating relative and/or... 

Hydrogen bonding is an important weak interaction encountered in gas, liquid, as well as solid phase. The hydrogen bond plays a very vital role in many life processes and is one of the most frequently used terms in chemistry and biology. Amides have several applications as drugs, antibacterials and antifungals. Different substituents can affect the acidity of amides. Investigation have shown that hydroxyl function group can increase the acidity of many organic molecules through interamolecular hydrogen bonding. The goal of this project is to investigate the acidity of cyclic amides and barbiturates by adding hydroxyl group in the gas and solution phase. All the gas phase optimizations and... 

Hydrogen bonding is an important weak interaction encountered in gas and liquid, as well as solid phase. The hydrogen bond plays a very vital role in many life processes and is one of the most frequently used terms in chemistry and biology. Beta diketones have several applications in organic, inorganic and analytical chemistry. Different substituents can affect the acidity of beta diketones. Investigation have shown that hydroxyl function group can increase the acidity of many organic molecules through interamolecular hydrogen bonding. The goal of this project is to investigate the acidity of hydroxyl containing beta diketones in the gas and solution phase. All the gas phase optimizations... 

This thesis is divided into three parts: In part I, structure and electronic properties of ionic liquids based on N7, N9-dimethylguaninium cation and α-amino acid (Gly, His, Phe, Try, and Tyr) anions and also ionic liquids based on 1-ethyl-3-methylimidazolium [emim]+ cation and alkyl-trifluoroborate ([RBF3]-, R=n-CmH2m+1 (m=1-5)) anions were discussed at the DFT(B3LYP)/6-311++G(d,p) level of theory. Then, the effect of chain length in anion on the nature and strength of interaction between cation and anion was investigated. Our results indicated that interaction energy values decrease with the increase in side chain size in anion. NBO and QTAIM results indicated that the interaction in these... 

In this work Nitroolefins were made by aromatic aldehydes consisting of electron withdrawing and electron donor groups. Afterward β-Bromo-β-nitrostyrenes were produced from interaction between nitroolefins and brom, at suitable temperature. After providing ingredients, micheal reaction (Friedel-crafts Pseudo-alkylation) between nitroolefins and various nucleophiles such as indoles was investigated. Finally desired micheal products were achived with high efficiency  

SiCl4 catalyzed Michael addition reaction of aliphatic and aromatic amines with different α,β- unsaturated compounds and one-pot three component Mannich reaction under solvent-free condition were investigated. β-amino carbonyl compound were synthesized in high yield in short reaction time. Furthermore, in the Mannich reaction good yield and excellent stereoselectivity were observed. In addition, the synthesis of 2-substituted benzothiazoles from aromatic aldehydes and 2 aminothiophenol in moderate to excellent yields in water in the presence of PTSA catalyst (10 mol%). This method provides a simple and efficient protocol in terms of mild reaction conditions, clean reaction profiles, small... 

Development of strategically important processes which are environmentally benign with simple methodology and work-up by low toxic material is currently reciving considerable attention.In recent years, dithiocarbamates (DTCs) and their synthesis with a green procedure have received many attention because of their undeniable applications.These synthetic compounds play important roles either in academia and industry. Here a simple, efficient and regiospecific method for synthesis of dithiocarbamates is described by one-pot three-component reaction of an amine, CS2 and alkyl vinyl ether via Markovnikov addition reaction in poly ethylene glycol (PEG) under a mild and green procedure with... 

This thesis is divided into three parts: In part I, conformational properties of neutral, anionic, cationic and zwitterionic forms of glutathione tripeptide were investigated by means of DFT-B3LYP method with 6-31+G (d,p) basis set. Results show that glutathione is a very flexible molecule and its conformational energy landscape is strongly influenced by forming intramolecular hydrogen bond and its charge. Conformation of each amino acid in glutathione tripeptide depends on its orientation within the peptide sequence in addition to the conformation of other amino acids within the chain. Investigation of intramolecular hydrogen bonds in these conformers by means of AIM analysis demonstrates... 

This thesis is divided into three parts: In part I, interactions of neutral and anionic forms of histidine with coinage metal nano clusters M3 (M = Au, Ag and Cu) are investigated. Results demonstrate that nonconventional M…H-O hydrogen bonds and M-X bonds (X = N, O) play stabilization roles in interactions of histidine and metal nano clusters. Presence of negative charge in ligand leads to increase of binding energy of complexes. In the next step, the effects of coinage metal nano clusters on the gas-phase acidity of weak organic acid (histidine) have been explored. The acidity of isolated histidine is compared with the acidity of its Au3–, Ag3– and Cu3–complexed species. Moreover, pKa... 

At the first part of project, different kinds of monodithiocarbamates were synthesized.In order to prepare these compounds two methods have been used:Reactions of amines and carbon disulfide in water and finally addition of Michael acceptors.Reaction of amines and carbon disulfide, then addition of alkyl halides under solvent-free conditions.Dithiocarbamate salts are prepared in ether by using CF3SO3CH3 as the methylation agent with resulted monodithiocarbamates at the first part of the project. These salts are found to be ionic liquids, which is important class of organic compounds.At the second part of project, the Michael additions of amines with divinyl sulfone are investigated in...