Özet:

Schiff-base-bearing new bis(thiosemicarbazone) derivatives were prepared from terephthalaldehyde and various thiosemicarbazides. FT--IR,$^{\, 1}$H NMR, $^{13}$C NMR, and UV--Vis spectroscopic methods and elemental analysis were used to elucidate the identification of the synthesized molecules. The in vitro antioxidant activity of the synthesized compounds was analysed with the 1,1-diphenyl-2-picryl hydrazyl free-radical-trapping process. The synthesized compounds exhibited lower antioxidant activity than the standard ascorbic acid. IC$_{50}$ values of the synthesized molecules measured from 3.81 $\pm $ 0.01 to 29.05 $\pm $ 0.11 $\mu$M. Among the synthesized compounds, compound 3 had the best antioxidant activity. Moreover, this study explained the structure--activity relationship of the synthesized molecules with different substituents in radical trapping reactions.

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