Pharmaceutical Nickel(II) Chelation Properties of 3-Hydroxyflaven, Deferiprone and Maltol Metal Chelators: A Density Functional Study

The present study describes the metal chelating ability of 3-Hydroxyflavene, Deferiprone and Maltol with Ni2+ metal ion using density functional theory. Structural analysis indicates that all three chelators bind to Ni2+ ion as a two-dentate chelator. Donor-acceptor interactions show an effective charge transfer from the oxygen atoms of the chelators towards Ni2+. Quantum theory of atoms in molecules analysis shows that the non-covalent interactions, mainly, electrostatic interactions play an important role in the complex formation of the selected chelators and Ni2+ ion. The TD-DFT study was applied in order to investigate the main electron transition. The ELF and LOL analysis was applied to confirm the result obtained from the QTAIM. Interaction energies and metal ion affinity were calculated for the [Ni(L)2] complexes and the results revealed a highly exothermic reaction during the chelation process. Natural bond analysis (NBO) and natural population analysis (NPA) and spin density evaluation were carried out in order to understand the charge transfer in the studied complexes. The NCI–RDG isosurface of the studied complexes show a complete set of electrostatic interactions, which encompass van der Waals interactions. The results verified that the selected chelators could be considered as effective chelating agents for Ni therapy.