Medium Effect on Solvation Free Energy, Dipole Moment and Molecular Reactivity of Naproxen

A computational study of medium effect on solvation free energy, dipole moment, polarizability, hyperpolarizability and different molecular properties like chemical hardness & softness, chemical potential, electronegativity and electrophilicity index of metronidazole have been reported in this paper. Becke, 3-parameter, Lee-Yang-Parr (B3LYP) level of theory with 6-31G (d,p) basis set was applied for gas phase and solution. The effect of solvent polarity on solvation free energy, dipole moment, polarizability, hyperpolarizability and molecular properties were calculated by employing Solvation Model on Density (SMD). The solvation free energies and dipole moment of metronidazole were found to be increased in nonpolar to polar solvents. The dipole moment of metronidazole was higher in different solvent than that of the gas phase. Moreover, from non-polar to polar solvents the chemical potential, electronegativity and electrophilicity index were increased. On the other hand, opposite relation was found in the case of chemical hardness and softness. The results obtained in this study may lead to understand the stability and reactivity of metronidazole and the results will be of assistance to use the title molecule as reaction intermediates and pharmaceuticals.Bangladesh Pharmaceutical Journal 19(1): 9-14, 2016

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Computational Study of Geometry, Solvation Free Energy, Dipole Moment, Polarizability, Hyperpolarizability and Molecular Properties of 2-Methylimidazole

Sultan Qaboos University Journal for Science [SQUJS] ◽

10.24200/squjs.vol21iss2pp89-101 ◽

2016 ◽

Vol 21 (2) ◽

pp. 89

Author(s):

Mohammad Firoz Khan ◽

Ridwan Bin Rashid ◽

Shahidul M. Islam ◽

Mohammad A. Rashid

Keyword(s):

Free Energy ◽

Dipole Moment ◽

Chemical Potential ◽

Computational Study ◽

Solvation Free Energy ◽

Molecular Properties ◽

Chemical Hardness ◽

Electrophilicity Index ◽

Reactivity Descriptors ◽

Solvent Systems

Ab initio calculations were carried out to study the geometry, solvation free energy, dipole moment, molecular electrostatic potential (MESP), Mulliken and Natural charge distribution, polarizability, hyperpolarizability, Natural Bond Orbital (NBO) energetic and different molecular properties like global reactivity descriptors (chemical hardness, softness, chemical potential, electronegativity, electrophilicity index) of 2-methylimidazole. B3LYP/6-31G(d,p) level of theory was used to optimize the structure both in the gas phase and in solution. The solvation free energy, dipole moment and molecular properties were calculated by applying the Solvation Model on Density (SMD) in four solvent systems, namely water, dimethylsulfoxide (DMSO), n-octanol and chloroform. The computed bond distances, bond angles and dihedral angles of 2-methylimidazole agreed reasonably well with the experimental data except for C(2)-N(1), C(4)-C(5) and N(1)-H(7) bond lengths and N(1)-C(5)-C(4) bond angle. The solvation free energy, dipole moment, polarizability, first order hyperpolarizability, chemical potential, electronegativity and electrophilicity index of 2-methylimidazole increased on going from non-polar to polar solvents. Chemical hardness also increased with increasing polarity of the solvent and the opposite relation was found in the case of softness. These results provide better understanding of the stability and reactivity of 2-methylimidazole in different solvent systems.

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EFFECTS OF SOLVENT POLARITY ON SOLVATION FREE ENERGY, DIPOLE MOMENT, POLARIZABILITY, HYPERPOLARIZABILITY AND MOLECULAR REACTIVITY OF ASPIRIN

International Journal of Pharmacy and Pharmaceutical Sciences ◽

10.22159/ijpps.2017v9i2.15853 ◽

2017 ◽

Vol 9 (2) ◽

pp. 217 ◽

Cited By ~ 1

Author(s):

Mohammad Firoz Khan ◽

Ridwan Bin Rashid ◽

Muhammed Mahfuzur Rahman ◽

Md. Al Faruk ◽

Md. Mustafezur Rahman ◽

...

Keyword(s):

Free Energy ◽

Dipole Moment ◽

Chemical Potential ◽

Solvent Polarity ◽

Solvation Free Energy ◽

Molecular Properties ◽

Chemical Hardness ◽

Electrophilicity Index ◽

First Order ◽

Solvent Systems

Objective: The aim of the study is to explore the effects of solvent polarity on solvation free energy, dipole moment, polarizability, first order hyperpolarizability and different molecular properties like chemical hardness and softness, chemical potential, electronegativity, electrophilicity index of aspirin which may lead to better understand the reactivity and stability of aspirin in different solvent systems.Methods: Becke, 3-parameter, Lee-Yang-Parr (B3LYP) level of theory with 6-31G(d,p) basis set was employed to conduct all type of calculations for both in the gas phase and in solution. The solvation free energy, dipole moment and molecular properties were calculated by applying the Solvation Model on Density (SMD) in four solvent systems namely water, methanol, ethanol and n-octanol.Results: The solvation energies steadily increased as the dielectric constant was decreased i.e. free energy increases with decreasing polarity of the solvent. The dipole moment of aspirin was found to be increased when going from non-polar to polar solvents. The dipole moment of aspirin was higher in different solvents than that of the gas phase. The polarizability and first order hyperpolarizability were also increased with the increasing dielectric constant of the solvent. Moreover, ongoing from non-polar to polar solvent the chemical potential, electronegativity and electrophilicity index were increased except in n-octanol. The chemical potential, electronegativity and electrophilicity index of aspirin in n-octanol was higher than that of ethanol. On the other hand, chemical hardness was increased with decreasing polarity of the solvent and the inverse relation was found in the case of softness.Conclusion: The calculated solvation free energy, dipole moment, polarizability, first order hyperpolarizability and molecular properties found in this study may lead to the understanding of stability and reactivity of aspirin in different solvent systems.

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Computational Study of Solvation Free Energy, Dipole Moment, Polarizability, Hyperpolarizability and Molecular Properties of Betulin, a Constituent of Corypha taliera (Roxb.)

Dhaka University Journal of Pharmaceutical Sciences ◽

10.3329/dujps.v16i1.33376 ◽

2017 ◽

Vol 16 (1) ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Mohammad Firoz Khan ◽

Ridwan Bin Rashid ◽

Md Aslam Hossain ◽

Mohammad A Rashid

Keyword(s):

Free Energy ◽

Dipole Moment ◽

Electrostatic Potential ◽

Molecular Electrostatic Potential ◽

Chemical Potential ◽

Solvation Free Energy ◽

Molecular Properties ◽

Mulliken Charge ◽

Chemical Hardness ◽

Electrophilicity Index

Ab initio calculations were carried out to studysolvation free energy, dipole moment, molecular electrostatic potential (MESP), Mulliken charge distribution, polarizability, hyperpolarizability and different molecular properties like global reactivity descriptors (chemical hardness, softness, chemical potential, electronegativity, electrophilicity index) of betulin. B3LYP/6-31G(d,p) level of theory was used to optimize the structure both in gas phase and in solution. The solvation free energy, dipole moment and molecular properties were calculated by applying the Solvation Model on Density (SMD) in six solvent systems namely water, dimethyl sulfoxide (DMSO), acetonitrile, n-octanol, chloroform and carbontetrachloride. The solvation free energy of betulin increases with decreasing polarity of the solvent. No systematic trend of hyperpolarizability with solvent polarity is found. Molecular electrostatic potential (MESP) and Mulliken population analysis (MPA) reveal that the most possible sites for nucleophilic attack are C30, H76 and H77 and electrophilic attack are O1 and O2 among the atoms in betulin. However, the dipole moment, polarizability, chemical potential, electronegativity and electrophilicity index of betulin increase on going from non-polar to polar solvents. Chemical hardness was also increased with decreasing polarity of the solvent and opposite relation was found in the case of softness. These results provide better understanding of the stability and reactivity of betulin in different solvent systems.Dhaka Univ. J. Pharm. Sci. 16(1): 1-9, 2017 (June)

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