This new azo dye 3-((2-(1H-indol-3-yl) ethyl) diazenyl) quinoline-2-ol was subsequently used to prepare a series of complexes with the metal ions of Cr+3, Cu+2, VO+2, Mn+2and Mo+6. The compounds identified by 1H and 13C-NMR, FT-IR, UV-Vis, mass spectroscopy, as well as TGA, DSC, and C.H.N., conductivity, magnetic susceptibility, metal and chlorine content. The results showed that the ligand behaves in a bidantate, and that the complexes gave octahedral, excepting for VO+2 square pyramid was given, that all complexes are non-electrolytes. The effectiveness of mention the compounds in inhibiting free radicals was evaluated by the ability to act as an antioxidant was measured using DPPH as a free radical and gallic acid as a standard substance, the IC50 value was determined, because the ligand was found to have a higher ability to inhibit free radicals, and the ability to inhibit the complexes varied according to the IC50 value. The anti-breast cancer efficacy of the compounds was evaluated at five concentrations each, the results showed that the IC50 value for ligand was 49.86 µg/mL, while the Mo complex gave 25.48 µg/mL, Cu complex gave 123.8 µg/mL, meaning that the Mo-complex gave a higher inhibition value than ligand and Cu. KEY WORDS: Antioxidant (DPPH), Azo dye complexes, Tryptamine, Thermal analysis, Anticancer Bull. Chem. Soc. Ethiop. 2025, 39(7), 1317-1334. DOI: https://dx.doi.org/10.4314/bcse.v39i7.7
