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

Stoichiometric reactions of 4,4'‐diacetylcurcumin ( HL ) with series of transition metal ions, namely Fe 3+ , Co 2+ , Ni 2+ and Zn 2+ , 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 Fe III , Co II , and Ni II complexes and reveal octahedral mononuclear complexes with the compositions [Fe(L) 3 ] and [M(L) 2 (MeOH) 2 ] (M = Co 2+ , Ni 2+ , Zn 2+ ) 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 IC 50 values of 20.91 ± 2.16 μg · mL –1 and 12.85 ± 1.85 μg · mL –1 , respectively. The Co II and Zn II complexes with IC 50 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 Fe III and Ni II complexes cause weaker reductions of the growth of the two tested cancer cell lines.