Cobalt(II) 2,4,4'-trihydroxydeoxybenzoin-3'-sulfonate was synthesized and characterized by IR, UV, ¹H NMR and elemental analysis, and single crystals were determined by X-ray single crystal diffraction. The scavenging effect of such cobalt compound on hydroxy radical was detected by fluorescent spectrophotometry while its scavenging effect on superoxide anion free radical was measured by ultraviolet spectrophotometry. The experimental results show that the crystal of title compound (C₂₈H₄₆CoO₂₆S₂) belongs to monoclinic space group C2/c with unit cell constants: a＝3.3937(3) nm, b＝0.85180(7) nm, c＝1.37455(11) nm, α＝90°, β＝97.8200(10)°, γ＝90°, V＝3.9365(5) nm³, Z＝4, D_c＝1.555 g/cm³, F(000)＝1924, R₁＝0.0329 and wR₂＝0.0852. The compound obtained can scavenge hydroxy radical and superoxide anion free radical effectively.

Key words: isoflavone, cobalt(II) 2,4,4'-trihydroxydeoxybenzoin-3'-sulfonate, crystal structure, antioxidant, free radical