Syntheses, Structures, and Bioactivities Evaluation of some Transition Metal Complexes with 4,4'‐Diacetylcurcumin

Abstract

Stoichiometric reactions of 4,4'‐diacetylcurcumin (HL) with series of transition metal ions, namely Fe3+, Co2+, Ni2+ and Zn2+, in methanol result in the corresponding homoleptic metal complexes. All the obtained complexes were characterized by elemental analysis, high resolution mass spectrometry, IR spectroscopy, magnetic moment and single‐crystal X‐ray diffraction. Structural analyses are unprecedentedly performed for the FeIII, CoII, and NiII complexes and reveal octahedral mononuclear complexes with the compositions [Fe(L)3] and [M(L)2(MeOH)2] (M = Co2+, Ni2+, Zn2+) for trivalent and divalent metal ions, respectively. In all complexes, the deprotonated ligands serve as monoanionic and bidentate ligands with (O,O)‐chelating β‐diketonate moieties. The free ligand HL exhibits considerable antiproliferative effects for the human MCF‐7 breast and HepG2 liver cancer cells with IC50 values of 20.91 ± 2.16 μg·mL–1 and 12.85 ± 1.85 μg·mL–1, respectively. The CoII and ZnII complexes with IC50 values in the range of 14.53–20.80 μg·mL–1 for MCF‐7 breast and 8.48–10.68 μg·mL–1 for HepG2 liver cancer cells show stronger antiproliferative effects than HL, the FeIII and NiII complexes cause weaker reductions of the growth of the two tested cancer cell lines.