Synthesis and characterization of silver(I) complexes bearing phenanthroline derivatives as ligands: Cytotoxicity and DNA interaction evaluation

In this work, three new silver(I) complexes, [Ag(NO2-NN)(tu)]NO3 (1), [Ag(NON-NN)(tu)]NO3 (2), and [Ag(CN-NN)(tu)]NO3 (3) and (R-N'N”= extended phenanthroline ligand with aromatic diamines replaced with R = NO2; NON (furazan); CN (nitrile); tu = thiourea) were synthesized and fully characterized by the techniques of UV–Vis spectroscopy; Infrared spectroscopy; 1H and 13C{1H} NMR; molar conductivity; elemental analysis (CHN); high-resolution electrospray ionization mass spectrometry (HRMS-ESI); and X-ray diffraction (compound 3). The compounds showed themselves to be stable to light, air, and the DMSO solution. The DNA interaction assays indicated that compounds 2 and 3 interacted with the DNA, by interaction via the minor groove. Compounds 2 and 3 showed outstanding cytotoxicity towards the human cell lines A2780cis (cisplatin-resistant ovarian carcinoma), the DU-145 (prostate cancer) cells, and MRC-5 (human lung fibroblasts). The IC50 (concentration of a compound that is required for 50% inhibition of the cell viability, in vitro) values substantially overcome that of cisplatin. This data has suggested that such a molecular design is promising to develop silver(I) complexes, with high anticancer activities.