Metal-ligand coordination and antiradical activity of a trichromium(III) complex with the flavonoid naringenin

The trinuclear chromium(III) complex [Cr₃O(CH₃CO₂)₆(L)(H₂O)₂] (where L is the monoanion of the flavonoid naringenin) was synthesized and characterized. Density functional theory (DFT) calculations and quantum theory of atoms in molecules (QTAIM) analysis show that the flavonoid binds to Cr^III as an O,O-bidentate ligand via the 5-hydroxy and 4-oxo groups. Reactions with 2,2-diphenyl-1-picrylhydrazyl (DPPH) indicate that the antiradical activity of this flavonoid-metal complex is enhanced in comparison with uncoordinated naringenin.