Sharif Digital Repository

The goal of this project was study on coordination behavior of the 14-membered macrocyclic ligand of type N2O2 aza-crown while it is attached to fullerene C60 nano-particle. For this purpose, firstly the macrocyclic ligand (Fig 3-1, L1) was synthesized and then was reacted with C60 (Fig 3-1, L2) of which the product was characterized by elemental analysis. Since the product was insoluble in any solvents, further study on its coordination chemistry was impossible. In a second procedure, the macrocyclic ligand was reacted with benzylbromide. The reaction mixture gave two macrocyclic ligands with different number of benzylic pendant groups (Fig 3-1, L3-L4). The products were separated by column... 

Nowadays, science of nano technology has been growing quickly in the past decade. Scientists implemented this technology in bioengineering, electronics and medicine extensively. Nano scale engineering is one of the interests of researchers, nano bearing as a nano scale structure and as an important part of nano machining plays an important role in micro and nano devices. The role of nano bearing is to decrease energy dissipation and increase the efficiency of nano machines. The main purpose of this study is to design and analyze an optimized nano ball bearing. In this regard, a new spherical super element is designed and presented. This super element is implemented in simulating the... 

A fullerene graph is a cubic and 3-connected plan graph that has exactly 12 faces of size5 and other faces of size 6, which can be regarded as the molecular graph of fullerene.In the irst part of this thesis we study some important deinitions and theorems whichused in the other parts.A matching of a graph G is a set M of edges of G such that no two edges of M sharean end-vertex; further a matching M of G is perfect if any vertex of G is incident with anedge of M. A matching M of G is maximum if |M| ? |N| for any other matching N in G. Amatching M is maximal if it is not a proper subset of some other matching in G. Obviously,any maximum matching in G is also a maximal matching. An... 

The purpose of this project is to synthesis of O2N3-azacrown ligands with 17 to 21 membered ring and investigation of their interaction with C60 according to increase ring size. These macrocyclic ligands can be used in C60 purification. In this project, change in macrocyclic cavity for finding the best macrocycle with appropriate cavity to C60 size has been considered. Firstly, five O2N3-azacrown ligands were synthesized and characterized by NMR spectroscopy and elemental analysis. Interaction of these ligands were considered by electronic spectroscopy applying Benesi-Hildebrand equation. According to the results, it was found that the best macrocycle for formation of stable complex with... 

Fullerenes are molecular solid materials which are composed of 3D closed shell carbon-only structure. As soon as mass production of fullerenes was performed, the synthesis and characterization of endohedral fullerenes having at least one non-carbon element in the hollow fullerene cage, was started (in which about 30 atoms inserted in it so far). Furthermore, because of low efficiency and purity of these nano-particles, nowadays characterization of fullerenes is one of the most important research fields. In this project, we firstly optimized the fullerene production parameters in an arc discharge reactor to reach convenient efficiency. Then, the synthesis of endohedral fullerene by vaporizing... 

In our previous work in this laboratory, macrocycle containingO_2 N_2 and O_2 N_3- donor set with various ring size were synthesized. The intraction of macrocyles with [60]fullerene were determined. In this research, we synthesized 22-membered aza-crown macrocycle ligand containing O_4 N_2- donor set and characterized by NMRspectroscopy. The intraction of macrocycle with [60]fullerene were also investigated by UV-Visible spectroscopy. The formation constant was determined applying Benesi--Hildebrand equation. The result has been showed that O_4 N_2 macrocyle had better complexation with [60]fullerene in comparision of O_2 N_3 and O_2 N_2 donor sets. Then, the interaction of O_4 N_2 with... 

One of the considerable issues in fullereneresearch is low yield of endohedral fullerene production.In this project, synthesis and optimization of endohedral metallofullereneproduction was undertaken byarc reactor applying vertical graphite electrodes, using vaporizing composite lanthanum-oxide-graphite-dopped rod. Increasing the efficiency of endohedral fullerrene production in sootwas followed applyingcarbide formation in electrode which was studied by X-ray diffraction(XRD), thermogravimetric analysis(TGA) and infrared (IR) spectroscopy. In addition, as a simple and fast method, the liquid column chromatography was applied in separation and purification of fullerenes as well as endohedral... 

One of the most common methods of producing fullerenes is electric arc vaporization of graphite. Due to the low yield and purity of the nanoparticles in this method, the synthesis and isolation of the area research is important. In this work, the production was improved in a multi-channel arc reactor in which having horizontal graphite electrodes. The influence of various operational parameters such as pressure of inert gas, spark time, interval time between two sparks, voltage and current were completely optimized. Moreover, the prominent advantage of the new reactor was increasing the number of manufacturing units, at least from one to three, which the production of fullerene was... 

In this research, a new group of N2O2–azacrown macrocyclic ligands with different macroring size from 15 to 18 was synthesized using one-pot facile and high yield reaction. The products were characterized applying FT-IR, 1H and 13C NMR spectroscopies as well as elemental analysis. The single crystal structure of 18-membered macrocyclic ligand was also determined by x-ray crystallography. The crystallographic data showed such strong inter-molecular hydrogen bonding which excluded their nitrogen-donor groups, and initial investigation with UV-Vis spectroscopy shows no intraction with [60]fullerene, despite of presence of these interacrtions in their parent macrocycles. The result of Job’s... 

By considering previous experiments undertaken in our laboratory on O2Nx (x=2,3) azacrown complexes with [60]fullerene, it was found that factors such as the macroring size, type and number of the donors groups in these macrocyclic ligands had significant effects on their selectivity towards [60]fullerene complexation. In this research, three N2O2N–azacrown macrocyclic ligand having uniform distribution of nitrogen atoms in macroring was synthesized using direct synthesis and high dilution method. The products were characterized applying 1H and 13C NMR spectroscopy as well as elemental analysis. Interaction of these ligands with [60]fullerene and Cu(II) were monitored by UV-vis spectroscopy... 

In this study, with respect to previous projects, we focused on size reduction of hollow and endohedral fullerenes research reactors. For this reason, we set up two reactors having 1/2 and 3 liters volumes and then such parameters as pressure, reactor temperature, arc duration time, arc time interval and the working electrical current through the electrodes circuit, in both reactors were optimized. The reactors, 3- and 1/2-liter reactors were of types of horizontal and vertical, respectively. In this project spatial angle between two electrodes were also found as effective variable on fullerenes yield in the 3-liters arc reactor for the first time. We found that upon correction of the... 

By considering previous works undertaken in our laboratory on the interaction between O2N2 azacrown and [60]fullerene using UV-vis spectroscopy. It was found that the significant interaction occurs in less than one hour. Extending this time in this research, the reaction between [60]fullerene with 15 to 19 membered N2O2-azacrown macrocyclic ligands was investigated during ten days. The new compounds L1, L2 were synthesized and characterized applying HPLC, ESI-Mass, TG, DSC, IR as well as elemental analysis. The interaction of new compounds with Cu(II) and Ni(II) and Co(II) using UV-vis spectroscopy showed that L2 gave the highest Kb value of cations/(L1, L2). Besides, it was found that the... 

The reaction of O2N2-donor naphthodiazacrown, with salicylaldehyde afforded new O3N2-donor macrocyclic ligands (L1-3naph) mounted with 1,3-diazcyclohexane subring in high yield. The product was characterized by IR, 1HNMR spectroscopy as well as elemental microanalysis and single crystal X-ray studies (just for L3naph). The interactions of [60]fullerene in presence and absence of base, Cu(II), Hg(II) and Zn(II) with L1-3naph were investigated employing fluorescence spectroscopy. The efficient fluorescence quenching of L1-3naph in presence of C60, Cu(II)( L1-2naph) and the fluorescence enhancement in presence of Hg(II) and Zn(II) indicated that the interaction with [60]fullerene Hg(II) and... 

In the present research, two series of N2O2- and N4O2-naphthadiaza-crown macrocyclic ligands with different macroring size, 15-21 memberd (L1-L7) were synthesized using direct method. The products were characterized by applying 1H and 13C NMR, IR spectroscopy, mass spectrometry and elemental analysis and in some cases by X-ray crystallography. Firstly, to study on emission properties of naphthadiaza-crown macrocyclic ligands as a fluorophore, we employed different amines as fluorescence quencher. It was observed that the quenching effects of 3o aliphatic amines like triethylamine were more pronounce than other group of amines. Also, the quenching constants for interactions of macrocyclic... 

New N4O6 molecular tweezers were synthesized from N2O2 benzo- and naphthodiazacrown macrocycles bearing benzylic dialdehydes as a flexible and semi-flexible spacer in a short time and at room temperature. The products were characterized by IR, 1H and 13C NMR spectroscopy as well as elemental microanalysis. The interactions of some of these tweezers with C60, Cu(II), Co(II), Ni(II), Zn(II), Hg(II) and Mn(II) were investigated by employing UV-Vis and fluorescence spectroscopy. Efficient fluorescence responses for 2NM3BD were observed in the presence of C60, Cu(II), Mn(II), Hg(II) and Zn(II). Meanwhile, the calculation of the association constants (K¬BH) employing Benesi-Hildebrand equation in... 

In the present research, a series of bimacrocyclic tweezer anchored through azobenzene moiety were synthesized and characterized by applying IR spectroscopy, 1H and 13C{1H} NMR, fluorescence spectroscopy, UV-visible spectroscopy, mass spectrometry and elemental analysis and in some cases by X-ray crystallography. Firstly, UV-visible spectroscopy established that the irradiation of the tweezers with UV light promoted the trans to cis isomerization. On the other hand, thermal cis-trans isomerization behavior of the azobenzene moiety in tweezers was surveyed in which the cis isomers were formed of the heating at 50 oC for 5 minutes. Where the -OH group was replaced with 4-toluenesulfonyl... 

A set of azacrown macrocyclic ligands bearing pyridine moiety (bp, 1p, 2p) were synthesized and characterized by single-crystal X-ray diffraction (SCXRD), elemental analysis, FT-IR, 1H and 13C NMR methods. The complexes of zinc tetraphenylporphyrin (ZnTPP) with the bp and 1p as the axial ligand were synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR, 1H and 13C NMR, fluorescence, UV-vis, cyclic voltammetry, together with TD DFT calculations. By employing this method for ZnTPPbenz and ZnTPPH complexes elucidated that the pyridine moiety was bonded through the fifth- coordination site on the zinc metal atom. In the following study, the coordination... 

In this project, in continuation of a PhD resreach undertaken in this research group in 2017, the synthesis and study of two new tweezer and linker molecule bearing azobenzene moiety were carried out, characterized by applying IR spectroscopy, ¹H and ¹³C {¹H} NMR, fluorescence spectroscopy, UV-visible spectroscopy, elemental analysis and X-ray crystallography. Firstly, interaction of T2 with meso-tetraphenylporphyrinato zinc(II) and aluminium tetraphenylporphyrinato were studied using the fluorescence spectroscopy. The formation constant of T2 in cis and trans isomer with ZnTPP was measured as 5.1(±0.4) ×108 and 2.0×108(±1074) dm6mol-2, respectively. The formation constant of T2 in with... 

In the present study, the coordination chemistry of an O4N4-tetrabenza-crown ether macrocyclic ligand L1 with M2+ (M= Cu, Cd, Hg, and Pb) was investigated by employing UV-visible, 1H-NMR spectroscopy in their solutions. According to the association constants calculated by 1H-NMR titrations, the complex formation stability for these closed shell cations was found in a series of Pb > Hg > Cd, leading to the larger cation, the better accommodation with L1. Moreover, the supramolecular interaction of L1 with fullerene C60 was also assessed by UV-visible spectroscopy. Meanwhile, the structure of [Cd(1)]2+ complex was determine by X-ray crystallographic method in their solid state. A square... 

Nanomachines are molecules inspired by natural molecular machines and are able to move and transport at the nanoscale. Due to the advancement of nanotechnology, the need to move materials and energy on a small scale is necessary more than ever. Nanocars are artificial molecular machines with chassis, axles, and wheels designed for nanoscale transport at materials’ surfaces. Understanding the dependence of surface dynamics of nanocars on the substrate’s physico-chemical properties is critical to the design of the transport properties of such man-made nanoscale devices. Among the multitude of potential substrates for the nanotransporters, graphene exhibits intrinsic ripples on its surface,...