Spectroscopic studies, DFT calculations, and cytotoxic activity of novel silver(I) complexes of hydroxy ortho-substituted-nitro-2 H-chromen-2-one ligands and a phenanthroline adduct

Silver(I) complexes of coumarin-based ligands and one of their phenanthroline (phen) adducts have been prepared and characterized using microanalytical data, molar conductivity, IR, ¹H and ¹³C NMR, UV-Vis, and atomic absorption (AAS) spectroscopies. The binding modes of the coumarin-based ligands and the most probable structure of their Ag(I) complexes were predicted by means of molecular modeling and calculations of their IR, NMR, and absorption spectra using density functional theory (DFT). The cytotoxicity of the compounds studied against human-derived hepatic carcinoma cells (Hep-G2) and a renal cancer cell line (A498) showed that the complexes were more cytotoxic than the clinically used chemotherapeutic, mitoxantrone. The compounds showed little interaction with DNA and also did not show nuclease activity but manifested excellent superoxide dismutase activity which may indicate that their mechanism of action is quite different to many metal-based therapeutics.