فهرست نشریات علمی دسترسی آزاد ایران

Schiff bases have shown to possess a wide range of electronic, optical and biological properties. In this manuscript, stability, HUMO-LUMO gap, first ionization energy, electrophilicity index, electron affinity, electronic chemical potential, chemical softness and hardness of keto-amine and phenol-imine tautomers of Schiff bases are theoretically investigated in the presence of polar organic solvent. (E)-4,6-dibromo-3-methoxy-2-[(p-tolylimino)methyl] phenol, a thermochromic Schiff base, is considered as a working model. The electronic structure of tautomers is characterized using the partial density of states (PDOS) of electrons. The results indicate that the decrease in dielectric constant of solvent is accompanied by increasing stability of tautomers. Also, the keto-amine ⥂ phenol-imine tautomerization is thermodynamically and kinetically facilitated by decreasing dielectric constant of solvent. The intramolecular O···HN and N···HO hydrogen bonds are found in keto-amine and phenol-imine forms, respectively. In order to better understanding of stability of tautomeric forms, the strength and nature of hydrogen bonds are evaluated using atoms in molecules (AIM), electrostatic potentials (ESP) and natural bond orbital (NBO) analyses.