Electrical Study of  Ionization Constant and Thermodynamic Parameters of Schiff bases Derived from 2-Nitrobenzaldehyde with Biological Activity Evaluation

Section: Article
Issue
Vol. 22 No. 3 (2026): Volume (22) Issue (3) September 2026
Pages
355-376

Abstract

The study involves using the compound (2-nitrobenzaldehyde) as a basic core for the preparation of three phenolic Schiff bases containing a hydroxyl group in the (ortho, meta and para) positions on the primary amine side. The structures of these Schiff bases were confirmed using IR, UV, and ¹H-NMR spectroscopy, as well as melting point measurements. The main objective is to determine the ionization constants (Ka) over a temperature range of (20–60 °C) using the electrical conductivity method, a precise and reliable technique. The results showed an increase in acidity with increasing temperature while maintaining a consistent order of Ka values. Thermodynamic analysis revealed that the ionization process in aqueous medium is non-spontaneous (ΔG = +), endothermic (ΔH = +), and accompanied by a decrease in entropy (ΔS = - ).In addition, the effect of temperature on the equivalent conductivity at infinite dilution was investigated with detailed analysis. Regarding biological activity, the compounds showed variation in inhibitory effects against S. aureus and E. coli. Compound (N1) showed the highest activity with inhibition zones of (19 mm) for Gram-positive and (7 mm) for Gram-negative bacteria, followed by (N2) with (18 mm) for Gram-positive, while (N3) showed balanced activity with (16 mm) and (15 mm), respectively. These findings highlight the promising potential of these compounds in chemical and biological applications.      

Keywords:

Conductivity, Ka, Schiff bases, Ionization Thermodynamics, Biological activity

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Authors

Amina Ayad Abdul-Karim Al-Dabagh

University of Mosul, College of Education for Pure Sciences, Department of Chemistry, Mosul, Iraq

Fedaa Hasan Marie Altaiea

University of Mosul, College of Education for Pure Sciences, Department of Chemistry, Mosul, Iraq

Identifiers

DOI: 10.33899/berj.2026.Vol22.Iss3.61528

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Electrical Study of  Ionization Constant and Thermodynamic Parameters of Schiff bases Derived from 2-Nitrobenzaldehyde with Biological Activity Evaluation . (2026). College of Basic Education Research Journal, 22(3), 355-376. https://doi.org/10.33899/berj.2026.Vol22.Iss3.61528
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Electrical Study of  Ionization Constant and Thermodynamic Parameters of Schiff bases Derived from 2-Nitrobenzaldehyde with Biological Activity Evaluation . (2026). College of Basic Education Research Journal, 22(3), 355-376. https://doi.org/10.33899/berj.2026.Vol22.Iss3.61528