Search for: fullerenes
Total 61 records
Article Journal of Coordination Chemistry ; Volume 62, Issue 20 , 2009 , Pages 3384-3390 ; 00958972 (ISSN) ; Tangeysh, B ; Sharif University of Technology
The effect of CoSALEN on anti-oxidative properties of fullerene C60 in the presence of O2 in cumene was investigated. A comparison was made between the role of the CoSALEN as a catalyst in the C60 oxidation and oxidation in the presence of an initiator, i.e., AIBN. A mechanism is proposed for the catalytic role of CoSALEN in oxidation of C60. Oxidation of octadecylaminofullerene C60 at the same conditions reveals that oxidation could be a result of hydroperoxidation of the unreacted sites of C60. We conclude that C60 as well as its aminoderivatives enhance the efficiency of CoSALEN in the oxidation of cumene due to their radical scavenging property of their unreacted double-bond sites. ©...
M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram
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...
M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram
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...
Strain effect on quantum conductance of graphene nanoribbons from maximally localized wannier functions, Article Physical Review B: Condensed Matter ; Volume 81, Issue 12, Article number 125409 , 5 March , 2010 ; Rafii-Tabar, H ; Iraji Zad, A. (Azam) ; Sharif University of Technology
Density-functional study of strain effects on the electronic band structure and transport properties of the graphene nanoribbons (GNR) is presented. We apply a uniaxial strain (ε) in the x (nearest-neighbor) and y (second-nearest-neighbor) directions, related to the deformation of zigzag- and armchair-edge GNRs (AGNR and ZGNR), respectively. We calculate the quantum conductance and band structures of the GNR using the Wannier function in a strain range from −8% to +8% (minus and plus signs show compression and tensile strain). As strain increases, depending on the AGNR family type, the electrical conductivity changes from an insulator to a conductor. This is accompanied by a variation in the...
Article Optoelectronics and Advanced Materials, Rapid Communications ; Volume 4, Issue 4 , 2010 , Pages 538-539 ; 18426573 (ISSN) ; Hosseinzadeh, M. A ; Sharif University of Technology
Let ∑ be the class of finite graphs. A topological index is a function Top from ∑ into real numbers with this property that Top(G) = Top(H), if G and H are isomorphic. is defined as half sum of the distances between all the pairs of vertices in a molecular graph. The goal of this paper is to further the study of Wiener index of special case of a chain of fullerenes
Synthesis and thermogravimetric analysis of inclusion complexes of O2N2-donor Aza-crown macrocyclic ligands with fullerene, Article Journal of Thermal Analysis and Calorimetry ; Volume 118, Issue 3 , 2014 , pp 1631-1637 ; ISSN: 13886150 ; Gholamnezhad, P ; Hatami, M ; Sharif University of Technology
A simple method for the formation of inclusion complex of fullerene with two O2N2-donor aza-crown macrocyclic ligands was introduced. The products were characterized using UV-vis and IR spectroscopies as well as HPLC, and ESI mass spectrometry. The ESI mass and elemental analysis data revealed that the ratio of macroring:fullerene were not the same. The binding capability of the macrorings as well as the number of the macroring addends to fullerene were investigated using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Considering percentage mass loss in different steps of TG and the enthalpy changes in DSC found for each of these products, the number...
Molecular dynamics simulation of orientation dependency in the shock-induced phase transition of C60 fullerene single crystals into amorphous diamond, Article Phase Transitions ; Vol. 87, Issue. 3 , 2014 , Pages 271-285 ; ISSN: 01411594 ; Naghdabadi, R ; Sharif University of Technology
A molecular dynamics simulation of the shock-wave propagation in the face-centered cubic (FCC) structured C60 fullerene along the <100>, <110> and <111> crystallographic directions is performed. For this purpose, the response of the material under different shock-wave loadings is studied through Hugoniot curves. Three regimes of the material behavior have been observed from fully elastic to elastic-plastic to plastic. The Hugoniot elastic limit and the phase transition are also investigated along different crystallographic directions. It is shown that the shock wave travels faster along the <110> and <111> directions than in the <100> direction in the material. Comparing the results with the...
A temperature-calibrated continuum model for vibrational analysis of the fullerene family using molecular dynamics simulations, Article Applied Mathematical Modelling ; Volume 80 , April , 2020 , Pages 115-125 ; Golzari, A ; Sharif University of Technology
Elsevier Inc 2020
In the present study, a model was proposed to determine the elastic properties of the family of fullerenes at different temperatures (between 300 and 2000 K) using a combination of molecular dynamics simulation and continuum shell theory. The fullerenes molecules examined here are eight spherical fullerenes, including C60, C80, C180, C240, C260, C320, C500, and C720. First, the breathing mode frequency and the radius of gyration of the molecules were obtained at different temperatures by molecular dynamics simulations using AIREBO potential. Then, these data were used in a continuum model to obtain the elastic coefficients of these closed clusters of carbon in terms of temperature changes....
Azahomofullerenes as new n-type acceptor materials for efficient and stable inverted planar perovskite solar cells, Article ACS Applied Materials and Interfaces ; Volume 13, Issue 17 , 2021 , Pages 20296-20304 ; 19448244 (ISSN) ; Prochowicz, D ; Bończak, B ; Fiałkowski, M ; Tavakoli, M. M ; Yadav, P ; Patel, M. J ; Gupta, S. K ; Gajjar, P. N ; Hong, C. K ; Sharif University of Technology
American Chemical Society 2021
Fullerene derivatives with a strong electron-accepting ability play a crucial role in enhancing both the performance and stability of perovskite solar cells (PSCs). However, most of the used fullerene molecules are based on [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), which limits the device performance due to difficulties in preparing high-quality and uniform thin films. Herein, solution-processable azahomofullerene (AHF) derivatives (abbreviated as AHF-1 and AHF-2) are reported as novel and effective electron-transport layers (ETLs) in p-i-n planar PSCs. Compared to the control PCBM ETL-based PSCs, the devices based on AHFs exhibit higher photovoltaic performances, which is...
Synthesis of Azacrown Ethers N2O2 Ligands Substituted on the Ullerene and Investigation of Its Coordination Properties, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram
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...
M.Sc. Thesis Sharif University of Technology ; Akbari, Saeed
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...
Synthesis and Optimization of Endohedral Metall of Ullerene Production in Arc Reactor Applying Vertical Graphite Electrodes, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram
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...
Synthesis of C60 and Endohedral Fullerenes in New Multi-Channel Arc Reactor Equipped with Horizontal Graphite Electrodes, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram
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...
The effect of amino  fullerene derivatives on pour point and rheological properties of waxy crude oil, Article Journal of Molecular Liquids ; Volume 211 , November , 2015 , Pages 308-314 ; 01677322 (ISSN) ; Miran Beigi, A. A ; Taheri, Z ; Ghanbari, B ; Sharif University of Technology
Abstract In this work, two  fullerene derivatives were employed as flow improvers for waxy crude oil to reduce problems caused by the crystallization of paraffin during the production and/or transportation of the crude oil. These amine-based derivatives of  fullerene have been applied as wax inhibitor for improvement of rheological performance as well as pour point depressant in a waxy crude oil. Moreover, the influence of these  fullerene derivatives on the viscosity and pour point was also investigated in an Iranian waxy crude oil sample. The  fullerene derivatives were simply prepared by stirring a solution of  fullerene and two lipophilic amines. The results similarly...
Spectroscopic evidence on improvement in complex formation of O2N2 aza-crown macrocyclic ligands with Cu(II) acetate upon incorporation with fullerene, Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 169 , 2016 , Pages 202-207 ; 13861425 (ISSN) ; Gholamnezhad, P ; Sharif University of Technology
Elsevier B.V 2016
The present paper reports the spectroscopic investigations on the complexation of Cu(II) with two macrocyclic ligands bonded to Fullerene (L1 and L2) measured in N-methylpyrrolidone (NMP) as solvent. On the basis of UV–vis-NIR spectroscopy applying Jobs method of continuous variation, typical 1:1 stoichiometries were established for the complexes of Cu(II) with L1, and L2. DFT calculations suggested that superior HOMO distributions spread over the nitrogen-donor (as well as somehow oxygen- donor in L2) groups of L1 and L2 macrocycles were the key factor for the observed Kb value enhancement. Thermodynamic stabilities for these complexes have also been determined employing...
Article Computational Materials Science ; Volume 122 , 2016 , Pages 38-45 ; 09270256 (ISSN) ; Ghaf Ghanbari, P ; Sharif University of Technology
Using seven bond-order potentials and five force fields, the fundamental natural frequency of C60,Ag(1) (breathing mode), and two other basic modes, namely Hg(1) (squashing mode) and T2g(1) are calculated. The same frequencies are derived through a DFT B3LYP/6-31G(d) calculation. Furthermore, the results are compared with Raman and IR scattering data, and previous quantum mechanics calculations, depicting the strength of each interatomic potential in predicting the vibrational properties of Buckminsterfullerene. AIREBO, which is formulated for analyzing hydrocarbons, shows the highest accuracy among all of the potentials under investigation. In general, bond-order potentials predict a...
Article Current Applied Physics ; Volume 17, Issue 1 , 2017 , Pages 72-77 ; 15671739 (ISSN) ; Ghaf Ghanbari, P ; Sharif University of Technology
Using Tersoff bond order potential, a vibrational analysis of the spherical fullerene family, namely C60, C80, C180, C240, C260, C320, C500, and C720 was performed. To evaluate the validity of our results, we have compared our simulation results with available experimental data and also with DFT B3LYP/6-31G(d) calculations. In general, molecular stiffness tends to decrease with increasing size, but its variation is limited in cases where mostly the tension-compression interaction sites are active such as the breathing mode. Furthermore, the bond length of each molecule is derived and compared with experimental and theoretical values calculated for graphene. Finally, vibrational frequencies...
Article International Journal of Engineering Science ; Volume 44, Issue 17 , 2006 , Pages 1156-1163 ; 00207225 (ISSN) ; Naghdabadi, R ; Sharif University of Technology
In this paper, nanoscale modeling of a multi-shell fullerene embedded in an elastic medium and its application to vibrational analysis is investigated. The spherical layers of the multi-shell fullerene are concentrically nested, with carbon-carbon van der Waals interactions between them. Also, the whole multi-shell fullerene is influenced by polymer-carbon van der Waals forces from the surrounding elastic medium. The elasticity generated by the carbon-carbon bonds is assumed to be distributed isotropically over the fullerene surfaces. Following derivation of explicit equations for the motion of the multi-shell fullerene, vibrational behavior of a double-shell fullerene is analyzed and...
Comparative Study of Anti-oxidant Property of Fullerene C60 and its Amine Derivatives: the Effect of Transition Metal Complexes, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram
Since the discovery of fullerene C60, its chemical and physical properties have been a hot topic in the field of research. For the past two decades remarkable developments achieved in the field of fullerenes chemistry. The aim of this study is comparative study of antioxidant property of fullerene C60 and its amine derivatives and the effect of transition metal complexes. At the outset the anti-oxidative property of fullerene C60 and its amine derivatives explored and it was found that by increasing the chain length of amines, the anti-oxidative property of aminofullerenes increased respectively. In next step the effect of CoSALEN complex on anti-oxidative property of fullerene was...
Synthesis of N2O2N Azacrown Macrocyclic Ligands and Comparative Study on the Complexation of Ligands with Fullerene and Cu(II), M.Sc. Thesis Sharif University of Technology ; Ghanbari, Bahram
By considering previous experiments undertaken in our laboratory on O2Nx (x=2,3) azacrown complexes with 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 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 fullerene and Cu(II) were monitored by UV-vis spectroscopy...