Abstract: This paper introduced the synthesis method of quercetin-bismuth complexes.The composition of the synthesized complexes was characterized by UV-visible,IR,1H NMR spectroscopies and synchronous thermal analysis techniques. 1H NMR spectrum displayed quercetin chelated with bismuth ions at 3′-OH position.This result was confirmed by simultaneous thermal analysis.The antioxidants activity of the complexes was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH).It was shown that DPPH radical scavenging activity of free quercetin was decreased after chelation of bismuth cation.

Key words: quercetin, quercetin bismuth complexes, synthesis, characterization, free radicals