ORIGINAL_ARTICLE
Hydrogen Abstraction Reaction of Hydroxyl Radical with 1,1-Dibromoethane and 1,2-Dibromoethane Studied by Using Semi-Classical Transition State Theory
The hydrogen abstraction reaction by OH radical from CH2BrCH2Br (R1) and CH₃CHBr2 (R2) is investigated theoretically by semi-classical transition state theory. The stationary points for both reactions are located by using ωB97X-D and KMLYP density functional methods along with cc-pVTZ basis. Single-point energy calculations are performed at the QCISD(T) and CCSD(T) levels of theory with different basis sets. The results show that the activation energies are very sensitive to effects of electron correlation and basis set. In order to correct basis set effects on the calculated energetic, a correction factor (CF) is determined from the energy difference between the MP2/cc-pVTZ and MP2/aug-cc-pVTZ levels. xij vibrational anharmonicity coefficients, needed for semi-classical transition state theory, are calculated at the KMLYP/cc-pVTZ level of theory. Thermal rate coefficients are computed over the temperature range from 200 to 3000 K and they are shown to be in accordance with available experimental data. The computed rate constants for the reactions R1 and R2 are fitted to the equation k(T)=A T^n exp[-E(T+T_0 )/(T^2+ T_0^2 ) ].
https://www.physchemres.org/article_4576_0231952fe9ac383581bc7a21c6bb5bbb.pdf
2014-12-01
123
130
10.22036/pcr.2014.4576
dibromoethane
hydroxyl Radical
Ab initio
Semi-classical transition state
rate constants
Vahid
Saheb
vahidsaheb@uk.ac.ir
1
Department of Chemistry, Shahid-Bahonar University of Kerman, Kerman 76169, Iran
LEAD_AUTHOR
Mohammad
Solimannejad
2
Quantum Chemistry Group, Department of Chemistry, Faculty of Sciences, Arak University, Arak 38156-8-8349, Iran
AUTHOR
ORIGINAL_ARTICLE
A Thermodynamic Study of the Interactions between Acetamide Derivatives and PCA-PEG-PCA Copolymers: ONIOM Calculations
To improve drug selectivity toward target cells, one interesting approach for drug delivery is to use polymer nanoparticles. A two-layered ONIOM Becke3- LYP: UFF calculation was carried out to study the structural and thermodynamic properties of the interaction between acetamide derivatives and the PCA-PEG-PCA copolymers. The Interaction enthalpies and the Gibbs free energies between acetamide derivatives as anti-HIV and polymeric nanoparticles in the gas and solution phases were calculated. The structure as well as the thermodynamics of optimized complexes was discussed from the biological point of view. In the gas phase, substitutes of phenyl, flurophenyl, 4-acetyl-2-bromophenyl, and 3-Methyl-acetate-thiophen-2-yl had the highest energies, and in the water phase, the enthalpies and Gibbs free energies of the interaction for most compounds were almost identical. In the both phases the interaction is relatively weak and copolymers can be used for drug delivery.
https://www.physchemres.org/article_4583_018faf48d94ce381e4cc98c06ab21d18.pdf
2014-12-01
131
136
10.22036/pcr.2014.4583
ONIOM2
Copolymer
Anti-HIV drug
Drug Delivery
Thermodynamic properties
Mohsen
Oftadeh
m_oftadeh@pnu.ac.ir
1
Payame Noor University
LEAD_AUTHOR
Nosrat
Madadi Mahani
nmmadady@gmail.com
2
Payame Noor University
AUTHOR
ORIGINAL_ARTICLE
How the Nonextensivity Parameter Affects Energy Fluctuations
In this article, the effect of the nonextensivity parameter on the energy fluctuations of nonextensive systems is studied in two different versions of the Tsallis statistical mechanics. Once a general expression has been reported for the energy fluctuations in the second version (Tsallis work in 1988), the energy fluctuations of an ideal gas and a harmonic oscillator are studied in the second and fourth(OLM choice for the mean energy constrain) versions of the Tsallis statistical mechanics. The results for the fourth version indicate that relative energy fluctuations are strongly affected by the nonextensivity parameter via the number of accessible states. In fact, in the case of subextensive systems, the nonextensivity parameter leads to fewer accessible states as compared to extensive systems and, therefore, smaller relative energy fluctuations are expected. For super-extensive systems, however, relative energy fluctuations are found to be larger than those in extensive systems because of the greater accessible states available. Our studies show that very large relative energy fluctuations are caused as a result of the un-normalized nature of the second version which, in some cases, limits its application.
https://www.physchemres.org/article_4610_2f7dd6bdcf824beeae06d33b5caac90f.pdf
2014-12-01
137
145
10.22036/pcr.2014.4610
Energy fluctuations
Nonextensive systems
Harmonic oscillator
Ideal gas
Tsallis statistical mechanics
Ezat
keshavarzi
keshavrz@iut.ac.ir
1
Physical Chemistry Group, Chemistry Department, Isfahan University of Technology, Isfahan 8415683111, Iran
LEAD_AUTHOR
Abbas
helmi
a.helmi@ch.iut.ac.ir
2
Physical Chemistry Group, Chemistry Department, Isfahan University of Technology, Isfahan 8415683111
AUTHOR
Mohammad
Kamalvand
kamalvand@yazd.ac.ir
3
Department of Chemistry, Faculty of Science, Yazd University, Yazd 89195741
AUTHOR
ORIGINAL_ARTICLE
Spin-polarized transport through a zigzag-edge graphene flake embedded between two armchair nanoribbons electrodes
We study the coherent spin-polarized transport through a zigzag-edge graphene flake (ZGF), using Hubbard model in the nearest neighbor approximation within the framework of the Green function’s technique and Landauer formalism. The system considered consists of electrode/ (ZGF)/electrode, in which the electrodes are chosen to be armchair nanoribbons. The study was performed for two types of electrodes i.e., armchair-edge graphene nanoribbons (AGNRs) and armchair-edge boron-nitride nanoribbons (ABNNRs). Our calculations of the electronic and transport properties of these systems show that both systems posses spin filtering properties, while the spin filtering is higher in the full graphene system than the second system with boron nitride nanoribbon electrodes. The spin filtering in these systems is due to the interaction of the spin of the carriers with the local zigzag-edge magnetism in ZGF. However, the reduction of the spin filtering property in the case of the system with boron-nitride nanoribbon electrodes could be due to the decrease in the effective spin interaction of boron atoms in the contact sites and magnetization of the zigzag-edge of the ZGF.
https://www.physchemres.org/article_4722_cc9d75f627ebacc2a5af3c25b8df8266.pdf
2014-12-01
146
150
10.22036/pcr.2014.4722
spin transport
graphene nanoribbons
boron-nitride nanoribbons
Hubbard model
Green function’s technique
maliheh
khoshgoftar maher
ma65maher1@gmail.com
1
...
LEAD_AUTHOR
nasser
shahtahmassebi
nasser@ferdowsi.um.ac.ir
2
...
AUTHOR
mahmood
rezaee roknabadi
roknabad@ferdowsi.um.ac.ir
3
...
AUTHOR
ORIGINAL_ARTICLE
Study of Activity Coefficient of Hydrochloric Acid in 2-Propanol-Water Mixture by Electromotive Force Measurement Method
This paper is mainly focusing on the determination of mean molal activity coefficient of HCl in aqueous acidic medium. The present investigations have been carried out to determine the activity coefficients of hydrochloric acid in 2-propanol water mixture solutions under various conditions to study the ion solvent interactions in different temperatures. The standard molar potential Em0 of the cell; Pt; H2(g) /HCl(m) x% 2-propanol; Hg2Cl2(S)/Hg have been determined in 10%; 20% and 30% (w/w) of 2-Propanol-water mixture solution at three different temperatures 308K, 313K and 318K and molality ranging from 0.005 to 0.1 mol Kg-1. Eo of the cell can be computed by modified Davies equation as below, where K= 2.3026(RT/F), A΄ = appropriate Debye-Hückel constant and Mean molal activity coefficient, The mean molal activity coefficients of hydrochloric acid in aqua organic media and temperature are also computed. The primary ion-solvent effects and the secondary ion-solvent effects are also reported.
https://www.physchemres.org/article_4775_fbd11b98e64960b6bee35eb4aae4f96c.pdf
2014-12-01
151
158
10.22036/pcr.2014.4775
Activity coefficient
Hydrochloric acid
2-propnol and Davies equation
Manoj
Ghosh
mkghosh01@yahoo.co.in
1
Chattisgarh Swami Vivekanand Technical University, Bhilai
LEAD_AUTHOR
Sanjay
Ghosh
drsanjayghosh@yahoo.com
2
Pt. Ravishankar Shukla University, Raipur
AUTHOR
Ashish
Ghosh
ashisg@gmail.com
3
Patna University, Patna
AUTHOR
ORIGINAL_ARTICLE
Vapor-Pressure Osmometry and Conductivity Determination of Salting-Out Effects in Aqueous Surface-Active Ionic Liquid 1-Dodecyl-3-methylimidazolium Bromide Solutions
Systematic studies on the vapor-liquid equilibria (VLE) and conductometric properties of aqueous solutions of model surface-active ionic liquid 1-dodecyl-3-methylimidazolium bromide ([C12mim]Br) are performed in the absence and presence of a large series of electrolytes in order to achieve a deeper understanding about the molecular mechanism behind the specific salt effect on the aggregation behavior of [C12mim]Br in aqueous solution. For this purpose, 6 chloride electrolytes (NaCl, KCl, NH4Cl, (CH3)4NCl, MgCl2 and FeCl3) and 5 sodium electrolytes (NaCl, NaNO3, Na2CO3, Na2SO4, and Na3Cit.) were used in order to individualize the effect of the anion and the cation. The values of the critical aggregation concentration (CAC) were obtained and it was found that all the investigated electrolytes have salting-out effect on the aggregation of [C12mim]Br in aqueous solutions, leading to significant downward shifts of the CAC. The magnitude of the shifts depends on the water-structuring nature of the electrolyte and follows the Hofmeister series. Furthermore the effect of electrolyte on the degree of anionic binding and thermodynamic parameters of aggregation for [C12mim]Br in aqueous solutions were determined.
https://www.physchemres.org/article_5483_c178648de3c08e5b9e00855d578dd187.pdf
2014-12-01
159
170
10.22036/pcr.2014.5483
Ionic Liquid
Aggregation
Vapor-pressure osmometery
conductivity
Salt effect
Rahmat
Sadeghi
rsadeghi@uok.ac.ir
1
LEAD_AUTHOR
Roonak
Golabiazar
rgolabiazar@uok.ac.ir
2
University of Kurdistan
AUTHOR
ORIGINAL_ARTICLE
Interplay Between Lithium Bonding and Halogen Bonding in F3CX•••YLi•••NCCN and F3CX•••NCCN•••LiY Complexes (X = Cl, Br; Y = CN, NC)
MP2 calculations with cc-pVTZ basis set were used to analyze intermolecular interactions in F3CX···YLi···NCCN and F3CX···NCCN···LiY triads (X = Cl, Br; Y = CN, NC) which are connected via halogen and lithium bonds. Those complexes with the role of LiY as halogen acceptor and lithium donor show cooperativity with energy values ranging between -1.97 and -2.92 kJ mol-1. Those complexes with simultaneous role of NCCN as halogen and lithium acceptor are diminutive with energetic effects between 1.24 and 1.86 kJ mol-1. Results of energy decomposition analysis revealed that the electrostatic interactions are the major source of the attraction in the title complexes. The nuclear quadrupole coupling constant values at the sites of halogen atoms can be regarded as good descriptors to quantify the degree of cooperative/diminutive effects in the title systems.
https://www.physchemres.org/article_5540_90bba91a7207ae502cd0123f69619ecb.pdf
2014-12-01
171
178
10.22036/pcr.2014.5540
Cooperativity
Halogen bonds
Lithium bonding
EDA
NQR
Mohammad
Solimannejad
solimannejadm@yahoo.com
1
Arak University
LEAD_AUTHOR
Elahe
Bayatmanesh
ebayatmanesh@yahoo.com
2
Department of Chemistry, Faculty of Sciences, Arak University, Arak 38156-8-8349, Iran
AUTHOR
Mehdi
Esrafili
esrafili@maragheh.ac.ir
3
Laboratory of Theoretical Chemistry, Department of Chemistry, University of Maragheh, Maragheh, Iran
AUTHOR
ORIGINAL_ARTICLE
A review of Fischer-Tropsch synthesis on the cobalt based catalysts
Fischer-Tropsch synthesis is a promising route for production of light olefins via CO hydrogenation over transition metals. Co is one of the most active metals for Fischer-Tropsch synthesis. Some different variables such as preparation parameters and operational factors can strongly affect the selectivity of Fischer-Tropsch synthesis toward the special products. In the case of preparation variables, several parameters such as catalyst preparation method, effect of different supports, and influence of promoters have been studied. Also, some operational factors including pretreatment conditions and experimental parameters such as temperature, pressure, and H2/CO ratio have been investigated. In addition, the stability of the Co-based catalyst is one of the most important characteristics. Therefore, catalyst deactivation is the main phenomenon and should be considered and controlled during the CO hydrogenation over the Co-based catalysts. Several factors such as poisoning, sintering, etc., lead to catalyst deactivation. According to the above-mentioned parameters and variables, we present here a review of Fischer-Tropsch synthesis for production of light olefins over the Co-based catalyst in a micro- fixed-bed reactor.
https://www.physchemres.org/article_5786_647d417dee049459909c87bb00826df1.pdf
2014-12-01
179
201
10.22036/pcr.2014.5786
Light olefins
Fischer-Tropsch synthesis
Co-based catalyst
Catalyst deactivation
Ali
Mirzaei
mirzaei@hamoon.usb.ac.ir
1
University of Sistan and Baluchestan
AUTHOR
Maryam
Arsalanfar
maryam_galavy@yahoo.com
2
Iranian Research Organization for Science and Technology (IROST)
LEAD_AUTHOR
Hamid
Bozorgzadeh
bozorgzadehhr@ripi.ir
3
Research Institute of Petroleum Industry
AUTHOR
Abdoreza
Samimi
a.samimi@hamoon.usb.ac.ir
4
University of Sistan and Baluchestan
AUTHOR
ORIGINAL_ARTICLE
Design, Construction and Calibration of a Laser Ionization Time-of-Flight Mass Spectrometer
A time-of-flight mass spectrometer (TOF-MS) developed in our laboratory at Isfahan University of Technology is described here. The TOF-MS instrument uses laser as the ionization source which provides an opportunity to investigate the ions formed in laser ablation or desorption. The TOF-MS has an ionization chamber containing an accelerator and an ion lens to focus the ions into a one meter linear flight tube mass analyzer. Laser beam enters the ionization chamber through quartz window and can be focused either on the accelerator plates or in between. Solid sample may be deposited on the accelerator plate. Gas samples can also be admitted into the ionization chamber perpendicular to the accelerator axis through a leak valve. Mass spectra were obtained for gas samples as well as test solid samples. For the gas phase ionization, the laser was focused in the space between the accelerator plates while for the solid samples the laser beam was focused on the sample deposited on the repeller plate of the accelerator. Operational condition of the instrument were examined and mass calibration was achieved by measuring the flight time of the known alkali ions; Li+, Na+, K+, Cs+ and Rb+. Ions of type Alk+(Alk.Halide)n were observed for all alkali salts. In addition, spectra of alkali earth salts were obtained and assigned. An average mass accuracy of 0.016% was obtained and a mass resolution of 540 (m/Dm) was achieved for benzaldehyde (m/z = 106) as a test sample. The instrument is capable of being used for MALDI analysis.
https://www.physchemres.org/article_5975_0b64fac745d057c8447eef74480da2f9.pdf
2014-12-01
202
216
10.22036/pcr.2014.5975
Time-of-flight
Mass spectrometry
Laser ionization
Alkali halides
Isotope pattern
Mahmoud
Tabrizchi
m-tabriz@cc.iut.ac.ir
1
Isfahan University of Technology
LEAD_AUTHOR
Hossein
Farrokhpour
farrokhphossein@gmail.com
2
Isfahan University of Technology
AUTHOR
Fateme
Abyar
f.abyarfirouzabady@ch.iut.ac.ir
3
Isfahan University of Technology
AUTHOR
Hajar
Azad
h_azad_706@yahoo.com
4
Isfahan University of Technology
AUTHOR
Maryam
Mirian
mmirian66@yahoo.com
5
Isfahan University of Technology
AUTHOR
Vahideh
ILbeigi
vahide_2005vb@yahoo.com
6
Isfahan University of Technology
AUTHOR
ORIGINAL_ARTICLE
Thermodynamic properties of polarized liquid 3He along different isentropic paths
The dependence of some thermodynamic properties of spin-polarized liquid 3He such as velocity of sound, adiabatic index, isentropic compressibility and temperature on the spin polarization has been investigated along different isentropic paths. The Lennard-Jones potential has been used in our calculations. It has been found that for higher values of entropy, the spin polarization has greater effect on velocity of sound and adiabatic index with respect to those of lower entropies. Also for a certain value of entropy and density, the isentropic compressibility is almost insensitive to the variations in polarization. Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract Abstract
https://www.physchemres.org/article_5960_7e3810a99c96a890bf3802542511f566.pdf
2014-12-01
217
228
10.22036/pcr.2014.5960
Polarized liquid 3He
isentropic paths
correlation function
velocity of sound
adiabatic index
Gholam
Bordbar
bordbar@susc.ac.ir
1
Shiraz University
LEAD_AUTHOR
S.
Hosseini
smyhosseini@yahoo.com
2
Shiraz University
AUTHOR
ORIGINAL_ARTICLE
Nature of Lithium Interactions with DNA Nucleobases: Theoretical Study
In the present study, the interactions of three different lithium species Li+, Li3+ and CH3Li with several different sites of the most stable tautomers of DNA nucleo-bases are presented. This investigation is based on the results of thermochemical properties, Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) analysis, obtained at B3LYP/6-311++G(d,p) level of theory. The calculated results showed that guanine and cytosine have more tendencies for interaction with lithium in all above three lithium species. Also, it was shown that for each tautomer of the same nucleobase, coordination mode of lithium highly affects the value of Metal Ion Affinity (MIA). Bidentate base has more lithium affinity and the carbonyl oxygen is generally preferred over amino nitrogen. Furthermore, the analysis revealed the electrostatic nature of interactions. Li+-DNA-Base has the most MIA value and CH3Li-DNA-Base has the least one.
https://www.physchemres.org/article_6028_35d36fb1b6695ab2380373737f0d3b26.pdf
2014-12-01
229
243
10.22036/pcr.2014.6028
Lithium cation
DNA nucleobase
Thermochemistry
Metal interaction
Ali
Pakiari
pakiariah@gmail.com
1
Shiraz University
LEAD_AUTHOR
Maryam
Farrokhnia
farrokhnia.m@gmail.com
2
Bushehr University of Medical Sciences
AUTHOR
ORIGINAL_ARTICLE
Materials Based on Carbazole for Organic Solar Cells Applications. Theoretical Investigations
The research in new organic π-conjugated molecules with specific properties has become one of the most interesting topics in fields of materials chemistry. These materials are promising for optoelectronic device technology such as solar cells. On the other hand, the use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. The Control of this parameter is essential to predict and study the electronic parameters for possible applications in optoelectronics. In this work, quantum chemical investigations have been performed to explore the optical and electronic properties of two compounds based on carbazole. Firstly, we have determined the effect of grafting the Fluorine atoms on their opto-electronic and physico-chemical properties. In addition to the solubility in the polar solvents and the modification in geometric parameters, the substitution of Fluorine destabilize the HOMO and LUMO levels, decreases the band gap energy and raises conjugation length. Electronic, optical and photovoltaic properties have been reported in order to predict the BHJ solar cell device efficiency for studied compounds.
https://www.physchemres.org/article_6071_1295f5dcd3d04c26076cc7082bfe9d67.pdf
2014-12-01
244
251
10.22036/pcr.2014.6071
π-conjugated molecules
Carbazole
TECEB
Fluorine TECEB
organic solar cells
TD-DFT
low band-gap
Electronic properties
Mohammed
Bouachrine
bouachrine@gmail.com
1
ESTM University Moulay Ismail
LEAD_AUTHOR
Fatima
AGDA
agdafatima2013@gmail.com
2
FS FES
AUTHOR
Mostapha
TALEB
mustaphataleb62@yahoo.fr
3
FES FES
AUTHOR
Tayeb
ABRAM
tayeb87abram@gmail.com
4
EST Meknès
AUTHOR
ORIGINAL_ARTICLE
Calculation of Thermodynamic Properties of the Quasi-one Dimensional Liquid 3He at Finite Temperature
We have used a variational approach to calculate some thermodynamic properties of the quasi-one dimensional liquid 3He such as the energy, entropy, free energy, equation of state and heat capacity at finite temperature. We have employed the Lennard-Jones potential as the inter-atomic interaction. We have seen that the total energy increases by increasing both temperature and density. As expected, it is seen that the entropy decreases by increasing density and decreasing temperature. There is no minimum point in the free energy curve, showing that there is not any bond state for the quasi-one dimensional liquid 3He. The results of our calculations indicate that the equation of state of this system becomes stiffer as the temperature increases. Our results for the specific heat show that there is not any lambda transition for this system.
https://www.physchemres.org/article_6130_aacd650065bcbed41e6788f770af00a1.pdf
2014-12-01
252
259
10.22036/pcr.2014.6130
Liquid 3He
Quasi-one dimension
Thermodynamic properties
Gholam
Bordbar
bordbar@susc.ac.ir
1
Shiraz University
LEAD_AUTHOR
M.
Rastkhadiv
ghbordbar@shirazu.ac.ir
2
Shiraz University
AUTHOR
ORIGINAL_ARTICLE
Antibacterial Activity of Short-Chained 1-Alkyl-3-methylimidazolium Bis(trifluoromethylsulfonyl) Imide Ionic Liquids
The antibacterial activity of a series of ionic liquids containing short-chained 1-alkyl-3-methylimidazolium cations ([Cnmim+]; n = 2, 4, 6 and 8) and bis (trifluoromethylsulfonyl) imide anion ([Tf2N]) against E. coli and B. subtilis was measured, for the first time. All ILs used in this work were synthesized and analyzed by Fourier transform infrared (FT-IR) spectroscopy, NMR, and Karl-Fischer titration. Antimicrobial activity was determined by the tube dilution method. The ILs investigated showed antibacterial activity against E. coli and B. subtilis. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were in the ranges of 0.041-6.39 mM and 0.67-12.78 mM, respectively. The antibacterial activity for ionic liquids with longer alkyl chain (n ≥ 4) increased with increasing alkyl chain length. The highest inhibition against E. coli was found for [C8mim][Tf2N] (MIC = 0.041 mM and MBC = 0.67 mM). The mechanism of action of these ionic liquids was bacteriostatic.
https://www.physchemres.org/article_6236_9cfb7a46b6ef0782f37e66f41a572d91.pdf
2014-12-01
260
269
10.22036/pcr.2014.6236
Ionic Liquid
Antibacterial Activity
Imidazolium salts
Bis (trifluoromethylsulfonyl) imide
Razieh
Jalal
razieh@um.ac.ir
1
Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad
LEAD_AUTHOR
Elaheh
K. Goharshadi
gohari@um.ac.ir
2
Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad
AUTHOR
Hashem
Sajjadi
shsajjadi@mehr.sharif.ir
3
Department of Chemistry, Sharif University of Tehran, Tehran, Iran
AUTHOR
Paul
Nancarrow
pnancarrow@aus.edu
4
Department of Chemical Engineering, American University of Sharjah, Sharjah, UAE
AUTHOR