Open AccessEFFECTS OF SOLVENT POLARITY ON SOLVATION FREE ENERGY, DIPOLE MOMENT, POLARIZABILITY, HYPERPOLARIZABILITY AND MOLECULAR REACTIVITY OF ASPIRIN
Author(s) -
Mohammad Firoz Khan,
Ridwan Bin Rashid,
Muhammed Mahfuzur Rahman,
Md. Al Faruk,
Md. Mustafezur Rahman,
Mohammad A. Rashid
Publication year - 2017
Publication title -
international journal of pharmacy and pharmaceutical sciences/international journal of pharmacy and pharmaceutical sciences
Language(s) - English
Resource type - Journals
eISSN - 2656-0097
pISSN - 0975-1491
DOI - 10.22159/ijpps.2017v9i2.15853
Subject(s) - solvation , chemistry , polarizability , hyperpolarizability , electronegativity , dielectric , dipole , solvent effects , solvent , computational chemistry , density functional theory , organic chemistry , molecule , materials science , optoelectronics
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.