mehdi fard - Academia.edu (original) (raw)
Papers by mehdi fard
RSC Adv., 2014
Selective oxidation of sulfides to corresponding sulfoxides using H2O2 as a green oxidant at room... more Selective oxidation of sulfides to corresponding sulfoxides using H2O2 as a green oxidant at room temperature have been investigated by a magnetic supported iron (iron(ii) acetylacetonate) as an efficient and recyclable heterogeneous catalyst with excellent sulfide conversion and good sulfoxide selectivity.
Structural Chemistry, 2011
Hydrogen bonding interactions between thymine nucleobase and 2′-deoxythymidine nucleoside (dT) wi... more Hydrogen bonding interactions between thymine nucleobase and 2′-deoxythymidine nucleoside (dT) with some biological anions such as F− (fluoride), Cl− (chloride), OH− (hydroxide), and NO3 − (nitrate) have been explored theoretically. In this study, complexes have been studied by density functional theory (B3LYP method and 6-311++G (d,p) basis set). The relevant geometries, energies, and characteristics of hydrogen bonds (H-bonds) have been systematically investigated. There is a correlation between interaction energy and proton affinity for complexes of thymine nucleobase. The nature of all the interactions has been analyzed by means of the natural bonding orbital (NBO) and quantum theory atoms in molecules (QTAIM) approaches. Donors, acceptors, and orbital interaction energies were also calculated for the hydrogen bonds. Excellent correlations between structural parameter (δR) and electron density topological parameter (ρ b) as well as between E(2) and ρ b have been found. It is interesting that hydrogen bonds with anions can affect the geometry of thymine and 2′-deoxythymidine molecules. For example, these interactions can change the bond lengths in thymine nucleobase, the orientation of base unit with respect to sugar ring, the furanose ring puckering, and the C1′–N1 glycosidic linkage in dT nucleoside. Thus, it is necessary to obtain a fundamental understanding of chemical behavior of nucleobases and nucleosides in presence of anions.
Journal of Theoretical and Computational Chemistry, 2013
Density functional theory (DFT) method and B3LYP/6-311++G(d,p) basis set were used to determine c... more Density functional theory (DFT) method and B3LYP/6-311++G(d,p) basis set were used to determine coordination geometries, binding strength, and metal ion affinity (MIA) for interaction of 2′-deoxythymidine (dT) with alkali metal cations including Li+, Na+ , and K+ . Calculations demonstrated that the interaction of dT with these cations is tri-coordinated η (O2, O4′, O5′). Among these cations, Li+ cation exhibited the most tendency for interaction with dT. Cations via their interaction with dT can affect the N-glycosidic bond length, the values of pseudorotation of the sugar ring, the orientation of base unit with respect to sugar ring and the acidity of O5′H, O3′H, and N3H groups in 2′-dT nucleoside. Natural bond orbital (NBO) analysis was performed to calculate the charge transfer and natural population analysis of the complexes. Quantum theory of atoms in molecules (QTAIM) was also applied to determine the nature of interactions. It was shown that in these complexes, (dT- Li+ , dT...
Journal of Physical Organic Chemistry, 2012
The optimized minimum‐energy geometries of different macrocyclic amines and their protonated stru... more The optimized minimum‐energy geometries of different macrocyclic amines and their protonated structures were determined by using ab initio and density functional theory (DFT) calculations. All the gas phase optimizations and energy calculations were performed at the DFT/B3LYP/6‐311++G(d,p) level of theory. The HF/6‐31 + G(d,p) level was used for all single point calculations in the solution phase. Geometry optimizations indicate that the most stable structures are stabilized by intramolecular hydrogen bonds. The proton affinity (PA) of macrocyclic amines is controlled by the strength of intramolecular hydrogen bonds of macrocyclic amines. These hydrogen bonds strongly influence the basicity of heteroatoms in macrocycles. The highest PA value among the studied macrocyclic amines was found to be 264.9 kcal mol−1 for structure 7. This is comparable with PA of proton sponges such as 1,8‐bis(dimethylamino)naphthalene. The solution phase calculations were carried out in the dimethyl sulfo...
Journal of Physical Organic Chemistry, 2012
The synthesis of modified versions of deoxyribonucleic acid is an area that is receiving much att... more The synthesis of modified versions of deoxyribonucleic acid is an area that is receiving much attention. The replacement of the nitrogen atom on the nucleobases with boron atom has provided insight into deoxyribonucleic acid and ribonucleic acid stability, recognition, and replication at the atomic level. In the present research, we investigated a detailed density functional theory study of the structural, tautomeric, base‐pairing ability, bond dissociation energy, and electronic properties of two boron analogues (i.e., boron substitutions at 4‐position and 5‐position of uracil) of uracil nucleobase. The effects of these modifications on theirs acid–base properties have been considered. Our goal is to gather data to help elucidate the structure and electronic properties of boron analogues of uracil.Density functional theory calculations were performed using a nonlocal hybrid B3LYP and 6‐311++G (d,p) atomic basis set. The result of calculation revealed that the canonical ‘keto’ form ...
Journal of Molecular Structure, 2014
ABSTRACT An efficient method for synthesis of 2-iminium-1,3-dithiolane as a new family of ionic l... more ABSTRACT An efficient method for synthesis of 2-iminium-1,3-dithiolane as a new family of ionic liquids with reaction of dithiocarbamates with methyl triflouromethanesulfonate was described. Theoretical study on the synthesized ionic liquids was also performed by quantum chemistry calculation. Geometry optimization on the ion pairs was carried out with the B3LYP/6-311++G(d,p) level of theory. The interaction energies were calculated, and corrected by the basis set superposition error (BSSE) calculated by the counterpoise method. The results of natural bond orbital (NBO) and quantum theory of atoms in molecules (QTAIM) analyses indicate that the interactions occur via hydrogen bonding between oxygen atom lone pairs (lp(O)) of triflouromethanesulfonate anion and antibonding orbitals of σ*C–H of 2-iminium-1,3-dithiolane cations. Also, the results of QTAIM analysis show that the hydrogen bonds are closed shell (electrostatic) in the nature. Finally, the 1H and 13C calculated chemical shifts at the B3LYP/6-311++G** level were in agreement with experimental chemical shifts for synthesized ionic liquids.
Journal of Fluorine Chemistry, 2013
Transactions of the American …, 2007
... Titre du document / Document title. Effect of fast neutron damage in linearity of a SiC semic... more ... Titre du document / Document title. Effect of fast neutron damage in linearity of a SiC semiconductor detector monitoring system. Auteur(s) / Author(s). MEHDI REISI FARD ;BLUE Thomas E. ; MILLER Don W. ; Revue / Journal Title. ...
RSC Adv., 2014
Selective oxidation of sulfides to corresponding sulfoxides using H2O2 as a green oxidant at room... more Selective oxidation of sulfides to corresponding sulfoxides using H2O2 as a green oxidant at room temperature have been investigated by a magnetic supported iron (iron(ii) acetylacetonate) as an efficient and recyclable heterogeneous catalyst with excellent sulfide conversion and good sulfoxide selectivity.
Structural Chemistry, 2011
Hydrogen bonding interactions between thymine nucleobase and 2′-deoxythymidine nucleoside (dT) wi... more Hydrogen bonding interactions between thymine nucleobase and 2′-deoxythymidine nucleoside (dT) with some biological anions such as F− (fluoride), Cl− (chloride), OH− (hydroxide), and NO3 − (nitrate) have been explored theoretically. In this study, complexes have been studied by density functional theory (B3LYP method and 6-311++G (d,p) basis set). The relevant geometries, energies, and characteristics of hydrogen bonds (H-bonds) have been systematically investigated. There is a correlation between interaction energy and proton affinity for complexes of thymine nucleobase. The nature of all the interactions has been analyzed by means of the natural bonding orbital (NBO) and quantum theory atoms in molecules (QTAIM) approaches. Donors, acceptors, and orbital interaction energies were also calculated for the hydrogen bonds. Excellent correlations between structural parameter (δR) and electron density topological parameter (ρ b) as well as between E(2) and ρ b have been found. It is interesting that hydrogen bonds with anions can affect the geometry of thymine and 2′-deoxythymidine molecules. For example, these interactions can change the bond lengths in thymine nucleobase, the orientation of base unit with respect to sugar ring, the furanose ring puckering, and the C1′–N1 glycosidic linkage in dT nucleoside. Thus, it is necessary to obtain a fundamental understanding of chemical behavior of nucleobases and nucleosides in presence of anions.
Journal of Theoretical and Computational Chemistry, 2013
Density functional theory (DFT) method and B3LYP/6-311++G(d,p) basis set were used to determine c... more Density functional theory (DFT) method and B3LYP/6-311++G(d,p) basis set were used to determine coordination geometries, binding strength, and metal ion affinity (MIA) for interaction of 2′-deoxythymidine (dT) with alkali metal cations including Li+, Na+ , and K+ . Calculations demonstrated that the interaction of dT with these cations is tri-coordinated η (O2, O4′, O5′). Among these cations, Li+ cation exhibited the most tendency for interaction with dT. Cations via their interaction with dT can affect the N-glycosidic bond length, the values of pseudorotation of the sugar ring, the orientation of base unit with respect to sugar ring and the acidity of O5′H, O3′H, and N3H groups in 2′-dT nucleoside. Natural bond orbital (NBO) analysis was performed to calculate the charge transfer and natural population analysis of the complexes. Quantum theory of atoms in molecules (QTAIM) was also applied to determine the nature of interactions. It was shown that in these complexes, (dT- Li+ , dT...
Journal of Physical Organic Chemistry, 2012
The optimized minimum‐energy geometries of different macrocyclic amines and their protonated stru... more The optimized minimum‐energy geometries of different macrocyclic amines and their protonated structures were determined by using ab initio and density functional theory (DFT) calculations. All the gas phase optimizations and energy calculations were performed at the DFT/B3LYP/6‐311++G(d,p) level of theory. The HF/6‐31 + G(d,p) level was used for all single point calculations in the solution phase. Geometry optimizations indicate that the most stable structures are stabilized by intramolecular hydrogen bonds. The proton affinity (PA) of macrocyclic amines is controlled by the strength of intramolecular hydrogen bonds of macrocyclic amines. These hydrogen bonds strongly influence the basicity of heteroatoms in macrocycles. The highest PA value among the studied macrocyclic amines was found to be 264.9 kcal mol−1 for structure 7. This is comparable with PA of proton sponges such as 1,8‐bis(dimethylamino)naphthalene. The solution phase calculations were carried out in the dimethyl sulfo...
Journal of Physical Organic Chemistry, 2012
The synthesis of modified versions of deoxyribonucleic acid is an area that is receiving much att... more The synthesis of modified versions of deoxyribonucleic acid is an area that is receiving much attention. The replacement of the nitrogen atom on the nucleobases with boron atom has provided insight into deoxyribonucleic acid and ribonucleic acid stability, recognition, and replication at the atomic level. In the present research, we investigated a detailed density functional theory study of the structural, tautomeric, base‐pairing ability, bond dissociation energy, and electronic properties of two boron analogues (i.e., boron substitutions at 4‐position and 5‐position of uracil) of uracil nucleobase. The effects of these modifications on theirs acid–base properties have been considered. Our goal is to gather data to help elucidate the structure and electronic properties of boron analogues of uracil.Density functional theory calculations were performed using a nonlocal hybrid B3LYP and 6‐311++G (d,p) atomic basis set. The result of calculation revealed that the canonical ‘keto’ form ...
Journal of Molecular Structure, 2014
ABSTRACT An efficient method for synthesis of 2-iminium-1,3-dithiolane as a new family of ionic l... more ABSTRACT An efficient method for synthesis of 2-iminium-1,3-dithiolane as a new family of ionic liquids with reaction of dithiocarbamates with methyl triflouromethanesulfonate was described. Theoretical study on the synthesized ionic liquids was also performed by quantum chemistry calculation. Geometry optimization on the ion pairs was carried out with the B3LYP/6-311++G(d,p) level of theory. The interaction energies were calculated, and corrected by the basis set superposition error (BSSE) calculated by the counterpoise method. The results of natural bond orbital (NBO) and quantum theory of atoms in molecules (QTAIM) analyses indicate that the interactions occur via hydrogen bonding between oxygen atom lone pairs (lp(O)) of triflouromethanesulfonate anion and antibonding orbitals of σ*C–H of 2-iminium-1,3-dithiolane cations. Also, the results of QTAIM analysis show that the hydrogen bonds are closed shell (electrostatic) in the nature. Finally, the 1H and 13C calculated chemical shifts at the B3LYP/6-311++G** level were in agreement with experimental chemical shifts for synthesized ionic liquids.
Journal of Fluorine Chemistry, 2013
Transactions of the American …, 2007
... Titre du document / Document title. Effect of fast neutron damage in linearity of a SiC semic... more ... Titre du document / Document title. Effect of fast neutron damage in linearity of a SiC semiconductor detector monitoring system. Auteur(s) / Author(s). MEHDI REISI FARD ;BLUE Thomas E. ; MILLER Don W. ; Revue / Journal Title. ...