Azadeh Khanmohammadi - Academia.edu (original) (raw)

Papers by Azadeh Khanmohammadi

Research paper thumbnail of Structural analysis and electronic properties of a homodinuclear erbium(III) complex bridged by the polyazine ligand 2,2′-bipyrimidine

Inorganic Chemistry Communications, 2009

Research paper thumbnail of Electronic sensors for alkali and alkaline earth cations based on Fullerene‑C60 and silicon doped on C60 nanocages: a computational study

Research paper thumbnail of Electronic sensors for alkali and alkaline earth cations based on Fullerene‑C60 and silicon doped on C60 nanocages: a computational study

Research paper thumbnail of DFT calculations, structural analysis, solvent effects, and non-covalent interaction study on the para-aminosalicylic acid complex as a tuberculosis drug: AIM, NBO, and NMR analyses

Journal of Molecular Modeling

Research paper thumbnail of A computational study on acetaminophen drug complexed with Mn+, Fe2+, Co+, Ni2+, and Cu+ ions: structural analysis, electronic properties, and solvent effects

Journal of Molecular Modeling

Research paper thumbnail of A DFT theoretical investigation on the interplay effects between cation-π and intramolecular hydrogen bond interactions in the mesalazine⋯Fe2+ binary complex

Theoretical Chemistry Accounts

Research paper thumbnail of Electronic sensors for alkali and alkaline earth cations based on Fullerene-C60 and silicon doped on C60 nanocages: a computational study

Journal of Molecular Modeling

Research paper thumbnail of Exploration of the Mutual Effects Between Cation–π and Intramolecular Hydrogen Bond Interactions in the Different Complexes of Mesalazine with Metal Cations of Alkali and Alkaline-Earth: A DFT Study

In the current research, a comparative study of the interplay effects between cation–π and intram... more In the current research, a comparative study of the interplay effects between cation–π and intramolecular hydrogen bond (IMHB) interactions is performed on the complexes of mesalazine with Li+, Na+, K+, Be2+, Mg2+ and Ca2+ cations using density functional theory (DFT). For this purpose, the mesalazine analogue and the equivalent values of 3-aminobenzoic acid complexes with the cited cations are selected as a set of reference points. In order to understand the mutual effects between these interactions, the descriptors of geometrical, binding energies, topological properties and charge transfer values are examined on complexes using the atoms in molecules (AIM) and natural bond orbital (NBO) analyses. Results indicate that with the exception of Be2+ complex, the coupling simultaneously weakens both of the interactions. Finally, the physical properties such as energy gap, chemical hardness as well as electronic chemical potential of complexes are systematically analyzed by using fronti...

Research paper thumbnail of DFT calculation of the interplay effects between cation–π and intramolecular hydrogen bond interactions of mesalazine drug with selected transition metal ions (Mn+, Fe2+, Co+, Ni2+, Cu+, Zn2+)

Theoretical Chemistry Accounts, 2021

Density functional theory calculations are performed to determine the effect of cation-π and intr... more Density functional theory calculations are performed to determine the effect of cation-π and intramolecular hydrogen bond (IMHB) interactions on each other in the formed complexes between transition metal cations (Mn+, Fe2+, Co+, Ni2+, Cu+, Zn2+) with mesalazine drug. The strength of these interactions is evaluated by energetic, geometric, spectroscopic and topological parameters to explore the mutual effects between them. Atomic charge distribution and characterization of bonds in the studied systems are investigated by natural bond orbital and atoms in molecules analyses, respectively. Our findings show that the presence of IMHB increases the energies of cation–π interaction for the divalent complexes and Co+ complex, while for the other monovalent complexes the reverse process is observed. The results also display that, in most cases, the coexistence of IMHB and cation–π interactions decreases the IMHB strength.

Research paper thumbnail of The Influence of Cation-π Interactions on the Strength and Nature of Intramolecular O...H Hydrogen Bond in Orthohydroxy Benzaldehyde Compound

Physical Chemistry Research, 2017

The influence of cation-π interactions on the strength and nature of intramolecular O...H hydroge... more The influence of cation-π interactions on the strength and nature of intramolecular O...H hydrogen bond has been investigated by quantum chemical calculations in orthohydroxy benzaldehyde (HBA) compound. Ab initio calculations have been performed at MP2/6-311++G** level of theory. Vibrational frequencies and physical properties such as chemical potential and chemical hardness of these compounds have been systematically explored. The natural bond orbital (NBO) analysis and the Bader’s quantum theory of atoms in molecules (QTAIMs) have also been used to elucidate the interaction characteristics of these complexes. The intramolecular O...H hydrogen bond has been putted in the categories weak to medium in the investigated systems. The results obtained from calculations and the topological parameters derived from the Bader theory suggest that the strongest interaction and the highest electron density at BCP (bond critical point) are related to the Be2+-HBA complex. The HOMO–LUMO energy h...

Research paper thumbnail of Interaction of Vitamin B3 with Parent Uracil and Anticancer Uracils: A Detailed Computational Approach

A detailed study on the formed complexes from interaction between vitamin B3 with parent uracil a... more A detailed study on the formed complexes from interaction between vitamin B3 with parent uracil and anticancer uracil's is performed using M06-2X/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels of theory. In the studied systems, the uracil's can be placed in three preferential interaction sites (A1–A3) in the vicinity of the vitamin B3. For each uracil group, three configurations corresponding to energetic local minima are obtained. Among the various hydrogen bonding sites, the A1 region of uracil's shows the strongest interactions at both levels of theory. The analyzed dimers are also stabilized by two hydrogen bonds (H-bonds). The predicted H-bonds in the formation of complexes are: O∙∙∙H-N and O(S)∙∙∙H-O. The topological properties of the electron density distribution are also analyzed in terms of the Quantum Theory of “Atoms in Molecules” (QTAIM). Furthermore, the natural bond orbital (NBO) analysis is applied to get a more precise insight about the nature of the H-bond...

Research paper thumbnail of Theoretical Study on the Interaction between 5-Fluorouracil Anticancer Drug and Nitrosamine as a Family of Potent Carcinogenic Compounds in Different Solvents: A Quantum Chemical Study

In this research, the effect of different solvents on the stability order, binding energy and hyd... more In this research, the effect of different solvents on the stability order, binding energy and hydrogen bond (H-bond) strength of Fluorouracil-Nitrosamine (FU–NA) complex is investigated by using the density functional theory (DFT). The calculations are conducted on M06-2X/6-311++G(d,p) level of theory for optimization of complex geometries and their monomers. Based on the average of the calculated H-bond energies, the H-bond strength in the gas phase is higher than the solution phase and in the polar solvents are close to each other and lower than the non-polar ones. Our findings also show that when the solvent effect is applied the binding energy of complex is significantly changed. The binding energy in the solution phase is also lower than the gas phase. Therefore, the stability in the polar solvents with respect to the water as natural solvent is higher than the non-polar ones. The natural bond orbital (NBO) analysis and the Bader’s quantum theory of “Atoms in Molecules” (QTAIM)...

Research paper thumbnail of A comparative study of interplay effects between the cation-π and intramolecular hydrogen bond interactions in the various complexes of methyl salicylate with Mn+, Fe2+, Co+, Ni2+, Cu+, and Zn2+ cations

Structural Chemistry, 2021

The interplay among two important noncovalent interactions involving aromatic ring is studied by ... more The interplay among two important noncovalent interactions involving aromatic ring is studied by means of density functional theory (DFT) calculations on complexes of methyl salicylate with Mn+, Fe2+, Co+, Ni2+, Cu+, and Zn2+ cations. The energetic, geometrical, spectroscopic, topological, and molecular orbital descriptors are applied to evaluate the strength of the cation-π and intramolecular hydrogen bond (IMHB) interactions. These outcomes are compared with the parent molecule of methyl salicylate and the corresponding results of benzene (BEN) complexes with the cited cations as a set of reference points. Based on the energetic conclusions, for the double-charge cations, the simultaneous presence of these interactions enhances the strength of the cation-π, while for the mono-charge cations, the reverse process is observed. On the other hand, for both type of the cations (mono- and double-charge), the coupling of noncovalent interactions reduces the strength of the IMHB in the studied systems. The computations in this study are discussed with the Bader theory of atoms in molecules (AIM), the natural bond orbital (NBO) analysis, and the frontier molecular orbital (FMO) theory.

Research paper thumbnail of Theoretical study on the interaction of phenylalaninal with group IA (Li + , Na + , K + ) and IIA (Be 2+ , Mg 2+ , Ca 2+ ) metal cations

Journal of the Chinese Chemical Society, 2021

Research paper thumbnail of Density functional theory study of the interplay between cation–π and intramolecular hydrogen bonding interactions in complexes involving methyl salicylate with Li+, Na+, K+, Be2+, Mg2+, Ca2+ cations

Computational and Theoretical Chemistry, 2021

Abstract In the present study, the DFT (density functional theory) calculations are performed to ... more Abstract In the present study, the DFT (density functional theory) calculations are performed to gauge the effect of cation-π and intramolecular hydrogen bond (IMHB) interactions on each other in the formed complexes between methyl salicylate and Li+, Na+, K+, Be2+, Mg2+ and Ca2+ cations. The energetic, geometrical, topological parameters and the results of population analysis are applied to investigate these interactions. The calculations are carried out by using the atoms in molecules (AIM) and natural bond orbital (NBO) analyses. The computational results indicate that the presence of IMHB decreases/increases the binding energies in the mono/divalent complexes. On the other hand, the mutual influences of the IMHB and cation–π interactions decrease the IMHB strength of the studied systems. Finally, the frontier molecular orbital (FMO) analysis is employed to calculate the DFT-based global reactivity indices such as energy gap, chemical hardness and electronic chemical potential.

Research paper thumbnail of Computational study of noncovalent interactions within the various complexes of para aminosalicylic acid and Cr2+, Mn+, Fe2+, Co+, Ni2+, Cu+, Zn2+ cations: exploration of the enhancing effect of the cation–π interaction on the intramolecular hydrogen bond

Theoretical Chemistry Accounts, 2020

The quantum chemical calculations are performed to investigate the effect of cation–π interaction... more The quantum chemical calculations are performed to investigate the effect of cation–π interactions on structural and electronic characterization of the various complexes of para aminosalicylic acid with mono- (Mn+, Co+, Cu+) and divalent (Cr2+, Fe2+, Ni2+, Zn2+) metal cations. Topological analysis of the atoms in molecules is applied to evaluate the nature of the considered interactions. Electron populations obtained from the natural bond orbital analysis also give insight into the electron nature of the studied systems. The achieved outcomes from calculations show that the strongest/weakest interactions belong to the divalent/monovalent complexes. Besides, one O–H···O intramolecular hydrogen bond (H-bond) is observed in the analyzed complexes. Our findings indicate that the H-bond of complexes is placed in the medium H-bonds category. In addition, it can be stated that the O–H···O H-bond is strengthened/weakened by cation–π interactions in the presence of divalent/monovalent complexes. The energy gap, electronic chemical potential, chemical hardness, softness, and electrophilicity index are also calculated by using frontier molecular orbitals.

Research paper thumbnail of The effect of cation–π interactions on the stability and electronic properties of anticancer drug Altretamine: a theoretical study

Acta Crystallographica Section C Structural Chemistry, 2020

The present work utilizes density functional theory (DFT) calculations to study the influence of ... more The present work utilizes density functional theory (DFT) calculations to study the influence of cation–π interactions on the electronic properties of the complexes formed by Altretamine [2,4,6-tris(dimethylamino)-1,3,5-triazine], an anticancer drug, with mono- and divalent (Li+, Na+, K+, Be2+, Mg2+ and Ca2+) metal cations. The structures were optimized with the M06-2X method and the 6-311++G(d,p) basis set in the gas phase and in solution. The theory of `Atoms in Molecules' (AIM) was applied to study the nature of the interactions by calculating the electron density ρ(r) and its Laplacian at the bond critical points. The charge-transfer process during complexation was evaluated using natural bond orbital (NBO) analysis. The results of DFT calculations demonstrate that the strongest/weakest interactions belong to Be2+/K+ complexes. There are good correlations between the achieved densities and the amounts of charge transfer with the interaction energies. Finally, the stability a...

Research paper thumbnail of Theoretical investigation on the non-covalent interactions of acetaminophen complex in different solvents: study of the enhancing effect of the cation–π interaction on the intramolecular hydrogen bond

Theoretical Chemistry Accounts, 2020

In the current research, a comprehensive study is performed on the non-covalent interactions of t... more In the current research, a comprehensive study is performed on the non-covalent interactions of the acetaminophen complex in the presence of various solvents. In addition, the effect of cation-π interaction on the strength and nature of the intramolecular hydrogen bond (H-bond) is explored by density functional theory method. The computations are performed using the M06-2X functional and the 6-311++G(d,p) basis set. The obtained results reveal that both interactions become stronger in the gas phase with respect to the solution phase. The "atoms in molecules" theory and the natural bond orbital method are also applied to get more details about the investigated interactions character. Based on the achieved outcomes, the H-bond of the studied complex is placed in the weak H-bond category. Our findings indicate that the intramolecular H-bond is strengthened by the cation-π interaction in the different solvents. Finally, the physical properties such as frontier molecular orbitals, energy gap, dipole moment, chemical hardness as well as electronic chemical potential are investigated to evaluate the electronic properties, stability and reactivity of the studied complex.

Research paper thumbnail of Molecular structure, QTAIM and bonding character of cation–π interactions of mono- and divalent metal cations (Li+, Na+, K+, Be2+, Mg2+ and Ca2+) with drug of acetaminophen

Theoretical Chemistry Accounts, 2019

The molecular modeling analysis via density functional theory (DFT) calculations is performed on ... more The molecular modeling analysis via density functional theory (DFT) calculations is performed on all the formed complexes from interaction between mono-and divalent metal cations (Li + , Na + , K + , Be 2+ , Mg 2+ and Ca 2+) with acetaminophen. The interaction energies are calculated by M06-2X method in the gas phase and the solution. The obtained structures are analyzed by topological parameters in terms of electron density (ρ) and its Laplacian (∇ 2 ρ) at the bond critical point (BCP) using the atoms in molecules (AIM) methodology. The evaluated results from calculations suggest that the strongest interaction and the highest electron density at BCP are related to the Be 2+ complex. In addition, the natural bond orbital (NBO) analysis is performed to investigate the charge distribution in the related complexes. The MEP (molecular electrostatic potential) is given the visual representation of the chemically active sites and comparative reactivity of atoms. Finally, the quantum molecular descriptors such as energy gap, electronic chemical potential, global hardness and electrophilicity index are calculated to evaluate the electronic properties, stability and reactivity of the analyzed complexes.

Research paper thumbnail of Theoretical Study of Various Solvents Effect on 5-FLUOROURACIL-VITAMIN B3 Complex Using PCM Method

Journal of the Chilean Chemical Society, 2019

In this article, a detailed study of the solvent effects on the stability order, binding energy a... more In this article, a detailed study of the solvent effects on the stability order, binding energy and hydrogen bond strength in 5-Fluorouracil-Vitamin B3 (FU-VB) complex is performed using M05-2X method with 6-311++G(d,p) basis set. Based on the average of the calculated H-bond energies, the H-bond strength of FU-VB complex in gas phase is more than solution phase. The binding energy in solution phase is also lower than the gas phase. Therefore, the stability of the studied complex increases in solution phase with respect to the gas phase. Furthermore, the topological properties of the electron density distribution are analyzed in term of the Bader Quantum Theory of "Atoms in Molecules" (QTAIM). The natural bond orbital (NBO) method is also applied to get a more precise insight into the nature of intermolecular interactions. Finally, the solvent effect on the frontier molecular orbital energies (HOMO and LUMO), chemical potential and hardness of FU-VB complex is investigated.

Research paper thumbnail of Structural analysis and electronic properties of a homodinuclear erbium(III) complex bridged by the polyazine ligand 2,2′-bipyrimidine

Inorganic Chemistry Communications, 2009

Research paper thumbnail of Electronic sensors for alkali and alkaline earth cations based on Fullerene‑C60 and silicon doped on C60 nanocages: a computational study

Research paper thumbnail of Electronic sensors for alkali and alkaline earth cations based on Fullerene‑C60 and silicon doped on C60 nanocages: a computational study

Research paper thumbnail of DFT calculations, structural analysis, solvent effects, and non-covalent interaction study on the para-aminosalicylic acid complex as a tuberculosis drug: AIM, NBO, and NMR analyses

Journal of Molecular Modeling

Research paper thumbnail of A computational study on acetaminophen drug complexed with Mn+, Fe2+, Co+, Ni2+, and Cu+ ions: structural analysis, electronic properties, and solvent effects

Journal of Molecular Modeling

Research paper thumbnail of A DFT theoretical investigation on the interplay effects between cation-π and intramolecular hydrogen bond interactions in the mesalazine⋯Fe2+ binary complex

Theoretical Chemistry Accounts

Research paper thumbnail of Electronic sensors for alkali and alkaline earth cations based on Fullerene-C60 and silicon doped on C60 nanocages: a computational study

Journal of Molecular Modeling

Research paper thumbnail of Exploration of the Mutual Effects Between Cation–π and Intramolecular Hydrogen Bond Interactions in the Different Complexes of Mesalazine with Metal Cations of Alkali and Alkaline-Earth: A DFT Study

In the current research, a comparative study of the interplay effects between cation–π and intram... more In the current research, a comparative study of the interplay effects between cation–π and intramolecular hydrogen bond (IMHB) interactions is performed on the complexes of mesalazine with Li+, Na+, K+, Be2+, Mg2+ and Ca2+ cations using density functional theory (DFT). For this purpose, the mesalazine analogue and the equivalent values of 3-aminobenzoic acid complexes with the cited cations are selected as a set of reference points. In order to understand the mutual effects between these interactions, the descriptors of geometrical, binding energies, topological properties and charge transfer values are examined on complexes using the atoms in molecules (AIM) and natural bond orbital (NBO) analyses. Results indicate that with the exception of Be2+ complex, the coupling simultaneously weakens both of the interactions. Finally, the physical properties such as energy gap, chemical hardness as well as electronic chemical potential of complexes are systematically analyzed by using fronti...

Research paper thumbnail of DFT calculation of the interplay effects between cation–π and intramolecular hydrogen bond interactions of mesalazine drug with selected transition metal ions (Mn+, Fe2+, Co+, Ni2+, Cu+, Zn2+)

Theoretical Chemistry Accounts, 2021

Density functional theory calculations are performed to determine the effect of cation-π and intr... more Density functional theory calculations are performed to determine the effect of cation-π and intramolecular hydrogen bond (IMHB) interactions on each other in the formed complexes between transition metal cations (Mn+, Fe2+, Co+, Ni2+, Cu+, Zn2+) with mesalazine drug. The strength of these interactions is evaluated by energetic, geometric, spectroscopic and topological parameters to explore the mutual effects between them. Atomic charge distribution and characterization of bonds in the studied systems are investigated by natural bond orbital and atoms in molecules analyses, respectively. Our findings show that the presence of IMHB increases the energies of cation–π interaction for the divalent complexes and Co+ complex, while for the other monovalent complexes the reverse process is observed. The results also display that, in most cases, the coexistence of IMHB and cation–π interactions decreases the IMHB strength.

Research paper thumbnail of The Influence of Cation-π Interactions on the Strength and Nature of Intramolecular O...H Hydrogen Bond in Orthohydroxy Benzaldehyde Compound

Physical Chemistry Research, 2017

The influence of cation-π interactions on the strength and nature of intramolecular O...H hydroge... more The influence of cation-π interactions on the strength and nature of intramolecular O...H hydrogen bond has been investigated by quantum chemical calculations in orthohydroxy benzaldehyde (HBA) compound. Ab initio calculations have been performed at MP2/6-311++G** level of theory. Vibrational frequencies and physical properties such as chemical potential and chemical hardness of these compounds have been systematically explored. The natural bond orbital (NBO) analysis and the Bader’s quantum theory of atoms in molecules (QTAIMs) have also been used to elucidate the interaction characteristics of these complexes. The intramolecular O...H hydrogen bond has been putted in the categories weak to medium in the investigated systems. The results obtained from calculations and the topological parameters derived from the Bader theory suggest that the strongest interaction and the highest electron density at BCP (bond critical point) are related to the Be2+-HBA complex. The HOMO–LUMO energy h...

Research paper thumbnail of Interaction of Vitamin B3 with Parent Uracil and Anticancer Uracils: A Detailed Computational Approach

A detailed study on the formed complexes from interaction between vitamin B3 with parent uracil a... more A detailed study on the formed complexes from interaction between vitamin B3 with parent uracil and anticancer uracil's is performed using M06-2X/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels of theory. In the studied systems, the uracil's can be placed in three preferential interaction sites (A1–A3) in the vicinity of the vitamin B3. For each uracil group, three configurations corresponding to energetic local minima are obtained. Among the various hydrogen bonding sites, the A1 region of uracil's shows the strongest interactions at both levels of theory. The analyzed dimers are also stabilized by two hydrogen bonds (H-bonds). The predicted H-bonds in the formation of complexes are: O∙∙∙H-N and O(S)∙∙∙H-O. The topological properties of the electron density distribution are also analyzed in terms of the Quantum Theory of “Atoms in Molecules” (QTAIM). Furthermore, the natural bond orbital (NBO) analysis is applied to get a more precise insight about the nature of the H-bond...

Research paper thumbnail of Theoretical Study on the Interaction between 5-Fluorouracil Anticancer Drug and Nitrosamine as a Family of Potent Carcinogenic Compounds in Different Solvents: A Quantum Chemical Study

In this research, the effect of different solvents on the stability order, binding energy and hyd... more In this research, the effect of different solvents on the stability order, binding energy and hydrogen bond (H-bond) strength of Fluorouracil-Nitrosamine (FU–NA) complex is investigated by using the density functional theory (DFT). The calculations are conducted on M06-2X/6-311++G(d,p) level of theory for optimization of complex geometries and their monomers. Based on the average of the calculated H-bond energies, the H-bond strength in the gas phase is higher than the solution phase and in the polar solvents are close to each other and lower than the non-polar ones. Our findings also show that when the solvent effect is applied the binding energy of complex is significantly changed. The binding energy in the solution phase is also lower than the gas phase. Therefore, the stability in the polar solvents with respect to the water as natural solvent is higher than the non-polar ones. The natural bond orbital (NBO) analysis and the Bader’s quantum theory of “Atoms in Molecules” (QTAIM)...

Research paper thumbnail of A comparative study of interplay effects between the cation-π and intramolecular hydrogen bond interactions in the various complexes of methyl salicylate with Mn+, Fe2+, Co+, Ni2+, Cu+, and Zn2+ cations

Structural Chemistry, 2021

The interplay among two important noncovalent interactions involving aromatic ring is studied by ... more The interplay among two important noncovalent interactions involving aromatic ring is studied by means of density functional theory (DFT) calculations on complexes of methyl salicylate with Mn+, Fe2+, Co+, Ni2+, Cu+, and Zn2+ cations. The energetic, geometrical, spectroscopic, topological, and molecular orbital descriptors are applied to evaluate the strength of the cation-π and intramolecular hydrogen bond (IMHB) interactions. These outcomes are compared with the parent molecule of methyl salicylate and the corresponding results of benzene (BEN) complexes with the cited cations as a set of reference points. Based on the energetic conclusions, for the double-charge cations, the simultaneous presence of these interactions enhances the strength of the cation-π, while for the mono-charge cations, the reverse process is observed. On the other hand, for both type of the cations (mono- and double-charge), the coupling of noncovalent interactions reduces the strength of the IMHB in the studied systems. The computations in this study are discussed with the Bader theory of atoms in molecules (AIM), the natural bond orbital (NBO) analysis, and the frontier molecular orbital (FMO) theory.

Research paper thumbnail of Theoretical study on the interaction of phenylalaninal with group IA (Li + , Na + , K + ) and IIA (Be 2+ , Mg 2+ , Ca 2+ ) metal cations

Journal of the Chinese Chemical Society, 2021

Research paper thumbnail of Density functional theory study of the interplay between cation–π and intramolecular hydrogen bonding interactions in complexes involving methyl salicylate with Li+, Na+, K+, Be2+, Mg2+, Ca2+ cations

Computational and Theoretical Chemistry, 2021

Abstract In the present study, the DFT (density functional theory) calculations are performed to ... more Abstract In the present study, the DFT (density functional theory) calculations are performed to gauge the effect of cation-π and intramolecular hydrogen bond (IMHB) interactions on each other in the formed complexes between methyl salicylate and Li+, Na+, K+, Be2+, Mg2+ and Ca2+ cations. The energetic, geometrical, topological parameters and the results of population analysis are applied to investigate these interactions. The calculations are carried out by using the atoms in molecules (AIM) and natural bond orbital (NBO) analyses. The computational results indicate that the presence of IMHB decreases/increases the binding energies in the mono/divalent complexes. On the other hand, the mutual influences of the IMHB and cation–π interactions decrease the IMHB strength of the studied systems. Finally, the frontier molecular orbital (FMO) analysis is employed to calculate the DFT-based global reactivity indices such as energy gap, chemical hardness and electronic chemical potential.

Research paper thumbnail of Computational study of noncovalent interactions within the various complexes of para aminosalicylic acid and Cr2+, Mn+, Fe2+, Co+, Ni2+, Cu+, Zn2+ cations: exploration of the enhancing effect of the cation–π interaction on the intramolecular hydrogen bond

Theoretical Chemistry Accounts, 2020

The quantum chemical calculations are performed to investigate the effect of cation–π interaction... more The quantum chemical calculations are performed to investigate the effect of cation–π interactions on structural and electronic characterization of the various complexes of para aminosalicylic acid with mono- (Mn+, Co+, Cu+) and divalent (Cr2+, Fe2+, Ni2+, Zn2+) metal cations. Topological analysis of the atoms in molecules is applied to evaluate the nature of the considered interactions. Electron populations obtained from the natural bond orbital analysis also give insight into the electron nature of the studied systems. The achieved outcomes from calculations show that the strongest/weakest interactions belong to the divalent/monovalent complexes. Besides, one O–H···O intramolecular hydrogen bond (H-bond) is observed in the analyzed complexes. Our findings indicate that the H-bond of complexes is placed in the medium H-bonds category. In addition, it can be stated that the O–H···O H-bond is strengthened/weakened by cation–π interactions in the presence of divalent/monovalent complexes. The energy gap, electronic chemical potential, chemical hardness, softness, and electrophilicity index are also calculated by using frontier molecular orbitals.

Research paper thumbnail of The effect of cation–π interactions on the stability and electronic properties of anticancer drug Altretamine: a theoretical study

Acta Crystallographica Section C Structural Chemistry, 2020

The present work utilizes density functional theory (DFT) calculations to study the influence of ... more The present work utilizes density functional theory (DFT) calculations to study the influence of cation–π interactions on the electronic properties of the complexes formed by Altretamine [2,4,6-tris(dimethylamino)-1,3,5-triazine], an anticancer drug, with mono- and divalent (Li+, Na+, K+, Be2+, Mg2+ and Ca2+) metal cations. The structures were optimized with the M06-2X method and the 6-311++G(d,p) basis set in the gas phase and in solution. The theory of `Atoms in Molecules' (AIM) was applied to study the nature of the interactions by calculating the electron density ρ(r) and its Laplacian at the bond critical points. The charge-transfer process during complexation was evaluated using natural bond orbital (NBO) analysis. The results of DFT calculations demonstrate that the strongest/weakest interactions belong to Be2+/K+ complexes. There are good correlations between the achieved densities and the amounts of charge transfer with the interaction energies. Finally, the stability a...

Research paper thumbnail of Theoretical investigation on the non-covalent interactions of acetaminophen complex in different solvents: study of the enhancing effect of the cation–π interaction on the intramolecular hydrogen bond

Theoretical Chemistry Accounts, 2020

In the current research, a comprehensive study is performed on the non-covalent interactions of t... more In the current research, a comprehensive study is performed on the non-covalent interactions of the acetaminophen complex in the presence of various solvents. In addition, the effect of cation-π interaction on the strength and nature of the intramolecular hydrogen bond (H-bond) is explored by density functional theory method. The computations are performed using the M06-2X functional and the 6-311++G(d,p) basis set. The obtained results reveal that both interactions become stronger in the gas phase with respect to the solution phase. The "atoms in molecules" theory and the natural bond orbital method are also applied to get more details about the investigated interactions character. Based on the achieved outcomes, the H-bond of the studied complex is placed in the weak H-bond category. Our findings indicate that the intramolecular H-bond is strengthened by the cation-π interaction in the different solvents. Finally, the physical properties such as frontier molecular orbitals, energy gap, dipole moment, chemical hardness as well as electronic chemical potential are investigated to evaluate the electronic properties, stability and reactivity of the studied complex.

Research paper thumbnail of Molecular structure, QTAIM and bonding character of cation–π interactions of mono- and divalent metal cations (Li+, Na+, K+, Be2+, Mg2+ and Ca2+) with drug of acetaminophen

Theoretical Chemistry Accounts, 2019

The molecular modeling analysis via density functional theory (DFT) calculations is performed on ... more The molecular modeling analysis via density functional theory (DFT) calculations is performed on all the formed complexes from interaction between mono-and divalent metal cations (Li + , Na + , K + , Be 2+ , Mg 2+ and Ca 2+) with acetaminophen. The interaction energies are calculated by M06-2X method in the gas phase and the solution. The obtained structures are analyzed by topological parameters in terms of electron density (ρ) and its Laplacian (∇ 2 ρ) at the bond critical point (BCP) using the atoms in molecules (AIM) methodology. The evaluated results from calculations suggest that the strongest interaction and the highest electron density at BCP are related to the Be 2+ complex. In addition, the natural bond orbital (NBO) analysis is performed to investigate the charge distribution in the related complexes. The MEP (molecular electrostatic potential) is given the visual representation of the chemically active sites and comparative reactivity of atoms. Finally, the quantum molecular descriptors such as energy gap, electronic chemical potential, global hardness and electrophilicity index are calculated to evaluate the electronic properties, stability and reactivity of the analyzed complexes.

Research paper thumbnail of Theoretical Study of Various Solvents Effect on 5-FLUOROURACIL-VITAMIN B3 Complex Using PCM Method

Journal of the Chilean Chemical Society, 2019

In this article, a detailed study of the solvent effects on the stability order, binding energy a... more In this article, a detailed study of the solvent effects on the stability order, binding energy and hydrogen bond strength in 5-Fluorouracil-Vitamin B3 (FU-VB) complex is performed using M05-2X method with 6-311++G(d,p) basis set. Based on the average of the calculated H-bond energies, the H-bond strength of FU-VB complex in gas phase is more than solution phase. The binding energy in solution phase is also lower than the gas phase. Therefore, the stability of the studied complex increases in solution phase with respect to the gas phase. Furthermore, the topological properties of the electron density distribution are analyzed in term of the Bader Quantum Theory of "Atoms in Molecules" (QTAIM). The natural bond orbital (NBO) method is also applied to get a more precise insight into the nature of intermolecular interactions. Finally, the solvent effect on the frontier molecular orbital energies (HOMO and LUMO), chemical potential and hardness of FU-VB complex is investigated.