Synthesis, spectroscopic investigation, and DFT study of N, N'-disubstituted ferrocene-based thiourea complexes as potent anticancer agents

In the present work, the synthesis, characterization (FT-IR, multinuclear (H-1 and C-13) NMR, AAS, Raman, and elemental analyses), DNA binding (cyclic voltammetry, UV-Vis spectroscopy), and in vitro biological screening of nine new ferrocene-incorporated thioureas (A1-A9) are reported. Furthermore, the single-crystal X-ray structure of compound A8 was also determined. The ferrocene-based N, N'-disubstituted thioureas were derived by allowing the ferrocenyl anilines to react with freshly prepared isothiocyanates under a N-2 atmosphere in dry acetone. The DNA binding studies performed by cyclic voltammetry and UV-Vis spectroscopy produced results that are in close agreement with one another for the binding constants (K) and an electrostatic mode of interaction was observed. The DFT/B3LYP method was used to determine the charge distribution and HOMO/LUMO energies of the optimized structure. The DFT calculated HOMO and LUMO energies correlate well with the experimentally determined redox potential values. The synthesized ferrocenyl thioureas exhibited good scavenging activity against the 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH). These complexes were also scanned for their in vitro cytotoxic activity against MCF-7 carcinoma cells, and also towards the non-cancerous cell line MCF-10A. The results showed modest cytotoxicity against the subjected cancer cell line compared with a standard chemotherapeutic drug (cisplatin). However, these ferrocenyl derivatives have fewer toxic effects in normal cells.