Terephthalaldehyde and isophthalaldehyde-derived Schiff bases: A study of structural, computational, and biological aspects

Abstract

Three new Schiff base derivatives using simple and economical aldehydes like terephthalaldehyde (TPA) and isophthalaldehyde (IPA), with different amine precursors, were successfully synthesized under moderate circumstances. These compound are designated as follows: (1E,1′E)-1,1′-(1,4-phenylene) bis (N-(5-methylthiazol-2 yl)methanimine)(4-PMTM)(L1), (1E,1′E)-1,1′-(1,3-phenylene) bis(N-(5-methylthiazol-2-yl) methanimine) (3-PMTM) (L2), and (1E,1′E)-N, N''-((1E,1′E)-1,3-phenylenebis(methaneylylidene)) bis(N'-(2-hydroxynaphthalen-1-yl)formimidamide)(PMHF)(L3). The synthesized compounds were characterized using IR, ¹H NMR, ¹³C NMR, elemental analysis, and thermogravimetric analysis (TGA). Their solubility was evaluated across various solvents. A single-crystal X-ray diffraction (SCXRD) study of L1 was conducted using MoKα radiation (λ = 0.7107 Å). Computational analyses, including DFT and molecular electrostatic potential (MEP) studies, were employed to optimize structures and assess electronic properties. Molecular docking revealed notable antibacterial potential, further supported by in silico ADME profiling, indicating drug-like behavior. In vitro antibacterial assays against MRSA, B. subtilis, and Escherichia coli identified L3 as the only active Schiff base.