The study of DNA interaction with the acetate bis(1,10-phenanthroline)silver(I) monohydrate in a solution is of interest both for understanding the mechanism of biological activity of silver compound and for forming ordered structures (DNA fibrils) that can be used to solve various problems in the field of nanotechnology. The analysis of changing the DNA conformation (secondary structure, persistent length and volume effects) during the interaction by the methods of UV spectroscopy with the analysis of DNA melting, circular dichroism, viscosity, flow birefringence, AFM (atomic force microscopy) and SEM (scanning electron microscopy) was performed. The formation of two types of complexes was observed. At lower concentration of compound in DNA solution, silver atoms form the coordination bonds with a macromolecule, while the released phenanthroline ligands intercalate between DNA bases. When the concentration of the compound increases, the phenanthroline ligands form an ordered “layer” around the helix. The excess of silver compounds in the DNA solution (with more than five silver atoms per base pair), DNA precipitation is observed with the formation of long fibrils. It was shown that the binding of silver to DNA during the formation of complexes provides further metallization of the resulting structures with the aid of reducing agents; phenanthroline ligands influence the result of such metallization.

The experimental study of the DNA interaction with three cadmium coordination compounds [Cd(phen)₃](CH₃CO₂)₂, [Cd(phen)₂(H₂O)₂](CH₃CO₂)₂, and [Cd₂(phen)₄(H₂O)₂](CH₃CO₂)₄ was carried out using spectrophotometry, viscosity, and dynamic light scattering methods. The role of the solution ionic strength (concentration of NaCl) was analyzed. All compounds can penetrate (fully or partly) to the major or minor DNA grooves. It was shown that, in addition to the important role of electrostatic interactions in the formation of the complex, intercalation of the 1,10-phenanthroline ligand occurs for compounds [Cd(phen)₂(H₂O)₂](CH₃CO₂)₂ and [Cd₂(phen)₄(H₂O)₂](CH₃CO₂)₄. Compound [Cd(phen)₃](CH₃CO₂)₂ binds to DNA externally. The coordination bond between cadmium and DNA was formed in DNA complexes with [Cd₂(phen)₄(H₂O)₂](CH₃CO₂)₄. Preliminary computer modeling of the DNA interaction with the compounds used was performed.

Types of binding with DNA and pharmacologic activity of 1,10-phenanthroline and electron-rich 1,10-phenanthrocyanine complexes of d-elements are discussed. The relationship of the electronic and geometric structure of 1,10-phenanthroline complexes of transition metals to their interaction with DNA molecules is analyzed. The concept of redox-mediated antibacterial, antiviral, and antitumor activity of 1,10-phenanthroline complexes of d-elements is formulated.