Ionization Constants of Oximes Using HF and PM3 Quantum Methods

Abstract

This study investigates the ionization constants of various chemical compounds using two theoretical methods, HF/6-31G and PM3, coupled with multiple regression analysis to correlate these constants with theoretically calculated physical variables. The variables considered include energy functions (HOMO, LUMO, hardness, chemical potential, electrophilicity index, ductility), thermodynamic functions (∆H, ∆G, ∆S), and dipole moments. The research aims to address the gap in accurately predicting ionization constants through theoretical calculations. The correlation coefficients (R2) were used to evaluate the relationship between practical ionization constants and theoretical variables. The strongest correlations were found with thermodynamic functions, particularly enthalpy (∆H). Multiple regression analysis identified the best predictors for ionization constants, achieving high R2 values (0.980 for HF/6-31G and 0.993 for PM3). These findings demonstrate a strong alignment between practical and theoretical ionization constants, highlighting enthalpy as the most influential variable. The study underscores the potential of computational chemistry methods to accurately predict ionization constants, aiding in the efficient design and analysis of chemical compounds.