Iron is one of the most important elements in biological systems and related processes to the oxygen transfer. Although the inadequate level of iron leads to physical disability, a high level of iron also plays a role in several diseases, including heart disease, diabetes and cancer. Iron chelators are species that facilitate iron removal. Experimental results have shown that iron chelators have strong antiplatelet properties against many cancers. In this study, for the first time, Deferasirox is conjugated to the superparamagnetic iron oxide nanoparticles (SPIONs) with the aid of APTMS linker, yielding iron-ligand complex (ligand = SPION-APTMS-DFX). The terminal methyl groups are considered as the substitutes for nanoparticles. Theoretical calculations were performed at M062X/6-311G(d,p) level to obtain the optimized structures of the iron complex in quintet, triplet, and singlet multiplicities. Natural bond orbital and quantum theory of atoms in molecules analyses were carried out to understand the nature of the complex bond character and electronic transitions in the complexes. The obtained results confirm a high affinity of Deferasirox to iron and show that the bond of metal ion and donor atoms of the ligand is covalent.

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