Synthesis, DFT investigation, and biological evaluation of a novel Au(III) Schiff base complex with antioxidant and anticancer activities

Abstract

A novel Schiff base ligand, 2-((Z)-((3-((E)-((benzo[d]oxazol-2-yl) imino) methyl)pyridin-2-yl)imino)methyl)phenol (BOYMPIMP), and its Au(III) complex were synthesized and characterized. To the best of our knowledge, this is the first reported Au(III) complex derived from this ligand. The ligand was prepared by Schiff base condensation, and the complex was synthesized using a 1:1 metal-to-ligand molar ratio. Structural characterization was performed using FTIR, UV–Vis, ¹H and ¹³C NMR, CHN analysis, molar conductivity, and magnetic susceptibility, confirming a square-planar Au(III) coordination environment. DFT calculations at the B3LYP/6-311G(d,p) level supported the proposed structure and revealed a HOMO–LUMO energy gap of 7.662 eV, indicating high electronic stability. Antioxidant activity was evaluated by DPPH, ABTS, and FRAP assays. The Au(III) complex exhibited significantly higher antioxidant activity than the free ligand, comparable to ascorbic acid. Cytotoxicity was assessed against MCF-7 and MCF-10A cell lines using the MTT assay. The Au(III) complex showed greater activity toward MCF-7 cells (IC₅₀ = 57.68 µg mL⁻¹) than the ligand (IC₅₀ = 173.4 µg mL⁻¹), with lower toxicity toward MCF-10A cells (IC₅₀ = 279.3 µg mL⁻¹), indicating selective anticancer potential. These findings identify the Au(III) complex as a promising antioxidant and anticancer candidate for further investigation.

KEY WORDS: Schiff bases, Au(III) complex, DFT, Antioxidant, Anticancer, Benzoxazole

Bull. Chem. Soc. Ethiop. 2026, 40(10), 2205-2220.                    

DOI: https://dx.doi.org/10.4314/bcse.v40i10.11