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Online ISSN : 2349-8080 Issues : 12 per year Publisher : Excellent Publishers Email : editorinchiefijcrbp@gmail.com |
In this study, the study included the calculation of fourteen ionic and aromatic compounds, which included eight oximes and six Schiff bases. The parameters of the ionization of the compounds under study were calculated at absolute temperature (293K) using molecular modeling programs. Methods that included semi-empirical calculations were AUSTEN MOMEL 1 (AM1), Hatree Fock (HF), and Density functional theory (DFT). The polarizable conductor calculation model (CPCM) was used to calculate the physical variables in the solution phase instead of the gas phase using ethanol as a solvent. The ionization constants were calculated using multiple Linear regression (MLR) analysis and using various descriptive variables selected to test their representatively of the observed variation in pKa values These variables include a Mullikan charge on the atoms of the hydroxyl and azomethine group (C = N), the length of the double bond, the angles values, the value of the fixed dipole moment, DIHADRAL, the total energy and the heat of the formation temperature), molecular properties such as HOMO, LUMO, Molecular hardness, electrolyte guide and chemical potential. These values were correlated with pKa values. In this relationship, the values of pKa were calculated theoretically. The results obtained showed that the HF method and the AM1 method were preferable to the EDP method, although all methods were able to complete this type of calculation And with a good efficiency in describing the effect of substituents on pKa values, these results were clearly indicated by the high correlation coefficients (R2) obtained from the regression analysis and the correlation between the practical values of pKa and those calculated theoretically.
