Synthesis, characterization, and evaluation of the interaction of DNA with a new silver(I) complex with diazafluorene-based ligands: Experimental and theoretical studies

In this research a novel four-coordinated silver(I) complex with N-donor chelating ligands with formula [Ag(L1)(L2)]NO3, (where 4,5-diazafluoren-9-one = L1 and N-(4,5-diazafluoren-9-ylidene)aniline = L2) has been prepared and characterized with spectroscopic methods (UV-Vis, FT-IR and 1HNMR), elemental analysis, and molar conductivity measurement. The DNA-complex binding mode has been investigated by electronic absorption titration, luminescence titration, and thermodynamic studies and the relationship between the structure and the biological properties has been discussed. The binding constants (Kb) and thermodynamic parameters (enthalpy, entropy, and Gibbs free energy changes) have been calculated. The theoretical studies of the complex structure in the DFT framework have predicted the tetrahedral N4 coordination geometry for Ag(I) center. The molecular docking has been carried out to determine the binding mode and the best orientation of the complex with DNA. The experimental and theoretical results reveal that the Ag(I) complex binds to CT-DNA with a moderate intercalation capability with the partial insertion of the planar ligands between the double-stranded DNA bases and binding constant of 1.66×105 M-1.