فهرست نشریات علمی دسترسی آزاد ایران

A novel Schiff base ligand (2E,3E)-3-((6-(((1E,2E)-1,2-diphenyl-2-(thiazol-2-ylimino) ethylidene) amino)pyridin-2-yl)imino)butan-2-one oxime derived from thiazol-2-amine was synthesized through a three-step procedure involving sequential condensation reactions of 2,6-diaminopyridine with diacetyl monoxime (compound A), followed by reaction with benzil (compound B), and finally with thiazol-2-amine to yield the target ligand (SBTOx-OH). A nano complex of the above ligand was prepared by reacting it with gold(III) chloride dissolved in ethanol. The ligand (SBTOx-OH) and its gold(III) complex were characterized using spectroscopic techniques including FTIR, ¹H-NMR, ¹³C-NMR, UV-Vis spectroscopy, atomic absorption, in addition to melting point determination, molar conductivity, elemental microanalysis (C.H.N), and magnetic susceptibility measurements. The complex was prepared in a 1:1 (M:L) ratio. The combined results of these measurements support that the geometry of the gold(III) complex is square planar. The cytotoxic activity of the ligand and its gold complex was evaluated against breast cancer cells (MCF-7), with a selectivity index (SI) of approximately 1.16 relative to normal human dermal fibroblast cells (HdFn). Although the gold complex exhibited a marginally lower IC₅₀ against MCF-7 (111.2 μg/mL) compared to the free ligand (122.86 μg/mL), the free ligand displayed a more favorable selectivity index (SI = 3.35 vs. 1.16). The modest SI of the gold complex indicates limited preferential toxicity toward cancer cells, and further structural optimization is required to improve the therapeutic window. It should be noted that no positive control drug was included in the cytotoxicity assay, which represents a limitation of the current study. Molecular docking against the EGFR tyrosine kinase (PDB: 3DKF) indicated moderate binding affinities for the synthesized compounds, though the correlation between docking scores and experimental cytotoxicity was not straightforward.