Theoretical Calculation of pka of some Aromatic Ketones compounds by AM1 methods

Abstract

In this study of nineteen aromatic ketones compounds, their structure is shown in the figure below. The ionization constants were calculated by a theoretical method through statistical correlation with regression analysis of the values of the practical ionization constants for these compounds with a number of theoretically calculated structural properties of these compounds. The structural properties were calculated using the (AM1) method. The bonds, angles , and charges on the atoms, while the second type included the energy variables, which included the highest occupied molecular orbita (HOMO) the lowest unoccupied molecular orbita (LUMO), hardness (η), the electronic chemical potential (μ) and the general electrophilic index (W) and the total energy. The single and multiple regression analysis was carried out using the Statistical Analysis Program (SPSS). The relationship between the theoretically calculated variables and the practically calculated ionization constants was evaluated through the correlation coefficients R 2, where it ranged from. Through the single regression analysis, it was found that there have a number of variables that have a strong correlation with the values of the practical ionization constants, and the most powerful of those variables was the charge on the oxygen atom number 8 in the carbonyl group. During the triple regression analysis, we obtained the best correlation strength for three theoretically calculated variables with the values of practical ionization constants.