Synthesis, characterization, theoretical studies and cellular cytotoxicity effects of nickel (II) complexes with 3-hydroxyflavene, deferiprone, and maltol chelating ligands

In the present study, three complexes with nickel central metal and with general formula [Ni(L)2]; where L is 3-hydroxy flavone (HLf), deferiprone (HLd) and maltol (HLm); synthesized and characterized by Infrared spectroscopy, mass spectroscopy, and elemental analysis. Studies have shown three ligands that used in this study, after coordination to metals, prevent the proliferation of cancer cells, so the anti-cancer property of the synthesized compounds was investigated by MTT assay against HeLa, MCF-7, MDA-MB-231, NALM-6, Neuro-2a, and L929; cell lines and cisplatin was used as a control. Furthermore, we investigate the ability of 3-hydroxy flavone (HLf), deferiprone (HLd) and maltol (HLm) chelating with nickel (II) metal ion using density functional theory in both gas and solvent phases, Through the M062x/6-311++G(d, P) surface and Gaussian09 calculation package. Structural analysis shows that all three chelators are bonded to Ni2+ via oxygen atoms of hydroxyl, and carbonyl groups. The receptor-acceptor interactions represent the effective charge transfer from the oxygen atoms of the chelators to the metal ions. The quantum theory of atoms in molecular analysis reveals noncovalent interactions, and it should be noted that mainly, electrostatic interactions play an important role in the formation of Ni-metal complexes. The TD-DFT study was performed to investigate the main electron transfer. ELF and LOL analyzes were also performed to confirm the results obtained through QTAIM analysis. Interaction energies and metal ion affinity were calculated for [Ni(L)2] complexes, and the results showed that we observed a very exothermic reaction during the chelating process. Natural bond analysis (NBO) was performed to understand the charge transfer in the studied complexes. The results confirmed that the selected chelators are suitable chelating agents for the treatment of nickel.