The work considers DNA complexes with silver ions and a silver coordination compound containing phenanthroline ligands. The formation conditions of luminescent silver nanoclusters and nanoparticles having a plasmon resonance are analyzed. It is shown that nanoclusters form on reducing silver ions after the formation of their coordination bonds with nitrogenous bases of the macromolecule. The [Ag(Phen)₂]NO₃ compound cannot form such a bond and interacts with DNA by intercalating one of the phenanthroline ligands into a double helix. The preliminary binding of cis-DDP with DNA hinders the formation of silver nanoclusters.