Showing papers by "Roya Ahmadi published in 2020"

Procarbazine adsorption on the surface of single walled carbon nanotube: DFT studies

Abstract: In this research, the performance of single-walled carbon nanotube (SWCN) as a sensor and nanocarrier for procarbazine (PC) was investigated by infra-red (IR), natural bond orbital (NBO), frontier molecular orbital (FMO) computations. All of the computations were done using the density functional theory method in the B3LYP/6-31G (d) level of theory The calculated negative values of adsorption energy, enthalpy changes, Gibbs free energy changes showed the PC interaction with SWCN is exothermic, spontaneous and experimentally possible. The increasing of specific heat capacity (CV) of SWCN after adsorption of PC showed the thermal conductivity improved during the interaction process and this nanostructure is an excellent sensing material for the detection of PC. The NBO results demonstrate in all of the evaluated conformers a chemical bond with SP3 hybridization is formed between the medicine and SWCN. The great values of thermodynamic constants showed the adsorption process is irreversible and SWCN is not a suitable nanocarrier for delivery of PC. The density of states (DOS) spectrums showed the bandgap of SWCN decreased sharply after the adsorption of PC and this nanomaterial can be used as a sensor for electrochemical detection of PC.

Adsorption of Tetryl on the Surface of B12N12: A Comprehensive DFT Study

Abstract: In this study, the adsorption of tetryl on the surface of boron nitride cage was evaluated by density functional theory. For this purpose, the structures of tetryl, B12N12, and the tetryl-B12N12 complexes were geometrically optimized. Then, IR and frontier molecular orbital calculations were performed on them. The calculated adsorption energies, Gibbs free energy changes (ΔGad), adsorption enthalpy changes (ΔHad) and thermodynamic equilibrium constants (Kth) revealed that the adsorption process of both explosives is experimentally feasible, spontaneous, exothermic and non-equilibrium. The specific heat capacity values (CV) showed that the heat sensitivity has been significantly reduced in the tetryl complexes with B12N12. The N-O and C-N bond lengths and the density values demonstrated that tetryl-derived products with boron nitride cage have higher explosive velocity and blasting pressure in comparison to the pure blasting materials without B12N12. The frontier molecular orbital parameters such as band gap, chemical hardness, electrophilicity, chemical potential and charge capacity were also studied and the results proved that boron nitride cage is an ideal electroactive sensing material in order to fabricate novel sensors for the determination of tetryl.

Adsorption of lomustin anticancer drug on the surface of carbon nanotube: A theoretical study

Abstract: The present study aimed to assess the adsorption of Lomustin on the single-walled carbon nanotube which has been examined using Density Functional Theory (DFT), agent in a solvent phase (water) at the B3LYP/6-31G (d) theoretical level. Initially, the structures of Lomustin, carbon nanotube, and Lomustin complexes with carbon nanotubes were designed in Gauss View in three different conformers and were optimized geometrically, on which IR and frontier molecular orbital computations were carried out. Adsorption energy values, Gibbs free energy changes (ΔGad), adsorption enthalpy changes (ΔHad), and equilibrium thermodynamic constants were estimated. The results showed that adsorption process was spontaneous, exothermic and non-equilibrium. The values of specific heat capacity and adsorption enthalpy indicate that this nanostructure can be used to build new thermal sensors to measure Lomustin. The results of molecule orbitals estimations showed that energy gap, after drug absorption on the nanotube surface, decreased significantly and the values of chemical hardness and dipole moment were studied after the interaction of drug with adsorbent and the results showed that drug solubility and reactivity, after adsorption on carbon nanotubes, increased significantly. According to the obtained results for adsorption of Lomustin, this nanostructure can be used as a sensing material in building new electrochemical sensors to measure this drug.

Adsorption of Tetranitrocarbazole on the Surface of Six Carbon-Based Nanostructures: A Density Functional Theory Investigation

Abstract: In this study, the interaction of Tetranitrocarbazole (TNC) with six various carbon-based nanostructures including carbon nanotubes, graphene, carbon nanocones and three fullerenes (C20, C24 and C60) was investigated by Density functional theory (DFT). The calculated adsorption energies, Gibbs free energy changes, enthalpy variations and thermodynamic equilibrium constants revealed that the adsorption of TNC is exothermic process, spontaneous, one-sided, non-equilibrium and experimentally feasible on the surface of all of the studied nano-adsorbents except carbon nanotube. The increasing of N–O and C–NO2 bond lengths after reacting with nano-substituents proved that the energetic and explosive properties of TNC has defused significantly. The computed density values substantiated the detonation pressure and explosive velocity of TNC have improved after adsorbing on the surface of C20.Some frontier molecular orbital parameters such as band gap, chemical hardness, electrophilicity, chemical potential and charge capacity were also studied and the results showed that C20 is an ideal candidate for being used as a sensing material in the construction of TNC conductometric sensor. Graphenecould also be utilized as an electroactive sensing material in the development of TNC selective potentiometric electrodes.

Evaluating Adsorption of Proline Amino Acid on the Surface of Fullerene (C60) and Carbon Nanocone by Density Functional Theory

Abstract: Determination of proline is of great importance and investigating the interaction of this amino acid with nanostructures play a key role in the construction of novel appropriate sensors for proline measurement. In this regard, proline adsorption on the surface of fullerene and carbon nanocone was studied by density functional theory. For this purpose, the structures of fullerene, nanocone, proline and proline-adsorbent complexes at two different configurations were optimized geometrically. Then, IR and Frontier molecular orbital calculations were done in the temperature range of 298.15-398.15 K at 10˚ intervals. The obtained adsorption energies, adsorption enthalpy changes, Gibbs free energy variations and thermodynamic equilibrium constants showed that the adsorption of proline on the surface of nanocone is exothermic, spontaneous, one sided and experimentally feasible. In this sense, proline adsorption on the fullerene is endothermic, non-spontaneous, balanced and experimentally impossible. The achieved specific heat capacity values reveal that carbon nanocone can be used in the development of thermal sensors for the determination of proline. The effect of temperature on the adsorption process was also checked out and the results indicate that 298.15 is the optimum temperature for the studied procedure. Some HOMO-LUMO parameters such as energy gap, electrophilicity, maximum charge capacity, chemical hardness and chemical potential were also evaluated. Accordingly, the findings demonstrate that carbon nanocone can be utilized in the electrochemical determination of proline.

Adsorption of Cytarabine on the Surface of Fullerene C20: A Comprehensive DFT Study

Abstract: In this study ، Cytarabine anticancer drug approached fullerene C20 and variations in the chemical properties and reactivity of Cytarabine (anti-cancer drug) the thermodynamic parameters of the formation of nano-derivatives of the Cytarabine with the fullerene C20 nanostructure were calculated. For this purpose, seven states proposed for the formation of nano-derivatives ، all compounds were geometric optimization. Then, the calculations for determining the thermodynamic parameters at a temperature range of 298.15° K to 103.10° K (every one degree) and at a constant pressure of 1 atm and gas phase as well as the aqueous solvent phase is done. All calculations were performed using the B3LYP density functional theory method and the 31G-6* base series using Gaussian, Nanotube Modeler, Gauss view and Spartan software. It was found the optimal temperature for the synthesis of both water and gas phase is 298° K. According to the calculations carried out in the gas phase, the adsorption of V isomer is more likely, but in the aqueous solvent phase, the adsorption of the VI isomer is more probable.

Adsorption of TNT on the surface of pristine and N-doped carbon nanocone: A theoretical study

Abstract: In this research, the performance of the carbon nanocone as an adsorbent and a sensing material for the removal and detection of trinitrotoluene (TNT) was investigated using the density functional theory. The atomic structures of TNT and its complexes with carbon nanocone were optimized geometrically. Infra-red (IR) and frontier molecular orbital computations were employed to evaluate the interaction of TNT with the carbon nanocone. The obtained negative values of adsorption energies, Gibbs free energy changes, adsorption enthalpy variations and great values of thermodynamic equilibrium constants revealed that the interaction of the TNT with carbon nanocone was exothermic, spontaneous and experimentally feasible. The effect of the nitrogen doping and temperature on the adsorption process was also evaluated and the results indicated that TNT interaction with N-doped carbon nanocone was stronger than that of pristine one. In addition, 298 K was the optimum temperature for the adsorption process. The specific heat capacity values revealed that the heat sensitivity was declined tangibly after the TNT adsorption on the surface of carbon nanocone. Besides, the frontier molecular orbital parameters such as bandgap, electrophilicity, maximum transferred charge proved that the carbon nanocone could be utilized as an excellent sensing material for the construction of new electrochemical sensors for TNT determination. Some structural and energetic features were also discussed in details.

Adsorption of melphalan anticancer drug on the surface of boron nitride cage (B12N12): A comprehensive DFT study

Abstract: In this study, boron nitride cage (B12N12) adsorption with Melphalan anticancer agent in solvent phase (water) was studied using the density function theory (DFT) method. First, the structure of the Melphalan, B12N12 and their derivatives were geometrically optimized in two different configurations, with a base set of 6-31G* and hybrid B3LYP functions. Then, IR calculations, frontier molecule orbital (FMO) studies, and molecular orbital analysis were performed. In addition, thermodynamic parameters including, Gibbs free energy (ΔGad) and enthalpy (ΔHad) variations indicated that the adsorption of Melphalan with B12N12 is intense, spontaneous, one-way and non-equilibrium. The effect of temperature was studied as well. The results proved that at K 305.15 the highest efficiency was achieved.

Investigating the performance of nano structure C60 as nano-carriers of anticancer cytarabine, a DFT study

Abstract: In this research study, stability, chemical properties, and thermodynamic parameters nano-derivatives of the cytarabine with the fullerene C60 nanostructure were calculated in the range of 298.15-310.15 K at the B3LYP/6-31G* level of theory. Possible isomers of the cytarabine (four different configurations) with C60 molecule were considered, and the effect of temperature on the thermodynamic parameters was studied. The adsorption energy, Gibbs free energy changes (ΔGad), enthalpy (ΔHad) variations, thermodynamic equilibrium constant, specific heat capacity, chemical hardness, energy gap, and electrophilicity were evaluated, as well. The results indicated that the adsorption of the cytarabine with fullerene C60 is spontaneous. In addition, the calculated specific heat capacity values revealed that, the C60 can be utilized as a sensing material in the construction of thermal biosensors for cytarabine determination.

Trinitroanisole Adsorption on the Surface of Boron Nitride Nanocluster (B12N12): A Computational Study

Abstract: This paper investigated boron nitride nanocage performance as an adsorbent and sensing material for removal and detection of trinitroanisole by density functional theory. The calculated adsorption energies, Gibbs free energy changes (ΔGad), adsorption enthalpy changes (ΔHad) and thermodynamic equilibrium constants (Kth) revealed the adsorption process is experimentally feasible, spontaneous, exothermic and Irreversible. The highly negative adsorption energy values and bond lengths between B12N12 and trinitroanisole indicated the interaction between the adsorbate and the adsorbent is a chemisorption process. The N-O and C-N bond lengths and the density values showed that trinitroanisole complexes with boron nitride cage have higher explosive velocity and detonation pressure than the pure trinitroanisole without B12N12. The frontier molecular orbital parameters such as band gap, chemical hardness, electrophilicity, chemical potential and charge capacity were also studied and the findings proved B12N12 is an excellent sensing material for fabricating novel electrochemical and thermal sensors for detection of trinitroanisole.

Binuclear Nickel(II) Complex Containing 6-Methyl-2,2'-bipyridine and Chloride Ligands: Synthesis, Characterization, Thermal Analyses, and Crystal Structure Determination

Abstract: A new binuclear complex of [{NiCl(6-mbipy)}2(μ-Cl)2] (1) was prepared from the reaction of NiCl2.6H2O and 6-methyl-2,2'-bipyridine (6-mbipy) in a mixture of methanol and acetonitrile. Suitable crystals of 1 for X-ray diffraction measurement were obtained by slow evaporation of the resulted green solution at room temperature. Complex 1 was characterized by spectral methods (IR, UV–Vis, and luminescence), elemental analysis (CHN), and single-crystal X-ray diffraction. The structure of 1 is centrosymmetric binuclear complex and each Ni(II) cation is five-coordinated in a slightly distorted square-pyramidal configuration. In this binuclear complex, the Ni…Ni distance is 3.533(1)A. Furthermore, the luminescence emission of the title complex was blue-shifted and is stronger than that of free 6-methyl-2,2'-bipyridine ligand. Thermal stabilities of this complex was also studied by thermogravimetric analysis.

QUANTUM-CHEMICAL INVESTIGATION OF THE COMPLEXATION OF TITANOCENE DICHLORIDE WITH C20 AND M+@C20 (M+ = Li, Na, K) CAGES

Abstract: In this study, the interaction of titanocene dichloride with C20 and M+@C20 (M+ = Li+, Na+, K+) cages is investigated using quantum mechanical methods. The M06-2X functional and the 6-311G(d,p) basis set are applied in these calculations. The bonding interactions between the C20 and M+@C20 clusters with the titanocene dichloride complex are examined through the energy decomposition analysis. The charge transfer between fragments is illustrated by the electrophilicity-based charge transfer (ECT). Also, the thermodynamic parameters of these interactions are calculated. Finally, the quantum theory of atoms in molecules analysis is used to assess BCP(C–Cl) within the C20 and M+@C20… titanocene dichloride complexes.