6-Thioguanine bimolecular formation for dual chelation of iron: DFT study.

[Display omitted] • Two single models of 6TG were investigated for Fe-chelation. • Three bimolecular models of 6TG were investigated for dual chelation of Fe. • S atom of 6TG was the dominant atomic position for Fe-chelation. • Complementary N atom of pyrimidine or imidazole rings assisted S for Fe-chelation. • N atom of imidazole ring helped S atom for F-chelation more than N atom of pyrimidine ring. • Dual chelation of Fe was successfully done for the investigated 6TG systems. 6-Thioguanine (6TG) was investigated in this work for chelating iron (Fe) by assistance of sulfur (S) atom through density functional theory (DFT) calculations. 6TG was first participated in Fe-chelation process to form S1 and S2 models by help of nitrogen (N) atom of pyrimidine and imidazole rings. The results indicated that S2 model could be stabilized better than S1 model with more appropriate value of binding energy (BE). Fe-mediated formation of bimolecular models were based on combining each of S1 and S2 models to yield S11, S12 and S22 models; S22 could work for the best model of dual chelation of Fe. Quadrupole coupling constants (Qcc) also approved significant changes of electronic properties at the atomic sites to show impact of Fe-chelation process on the properties of molecules. Hence, dual chelation of Fe by 6TG was proposed with this work to arise more insights about unknown anticancer functions of 6TG. [ABSTRACT FROM AUTHOR]