Abstract

STATISTICAL STUDY OF STABILITY CONSTANTS FOR SOME AZO IMINE PHENOLIC DYES THEORETICALLY BY USING PARAMETERIZED METHOD (PM3)

Assist. Prof. Dr. Mohammad Mahmoud Hussein Al-Niemi* and Mushtaq Saad Younes AL-Obaidy

ABSTRACT

In this study, the study included the calculation of nine Azo imine phenolic dyes, which included nine Schiff bases. The parameters of the stability of the compounds under study were calculated at absolute temperatures (283K, 293K, 303K, 313K and 323K) using molecular modeling programs. Methods that included semi-empirical calculations were Parameterized Method (PM3). 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 stability constants were calculated using multiple Linear regression (MLR) analysis and using various descriptive variables selected to test their representatively of the observed variation in stability constants (K) values. These variables include a charge of C1, charge of C5, charge(C1-C7), Bond OH1, dipole moment and hardness. These values were correlated with K values. In this relationship, the values of K were calculated theoretically. The results obtained showed that the Parameterized Method (PM3) were preferable to the EDP method, although the method were able to complete this type of calculation And with a good efficiency in describing the effect of substituents on K values at all temperatures, these results were clearly indicated by the high correlation coefficients (R2) obtained from the regression analysis and the correlation between the practical values of K and those calculated theoretically.

Keywords: Stability constants, Imines, Azo imine phenolic dyes and PM3.