Ionization Potentials of Nucleic Acid Intercalators

Abstract

Abstract. Nucleic acid based electronic devices have attracted particular interest over the past two decades due to its ability of long-range charge transport and self-assembly. The π-π interactions of the stacked bases are believed to be responsible for the long-range charge transport. The insertion of intercalators could alter electronic structure of the host nucleic acids which may influence the charge transport through the nucleic acid. The influence of intercalators on charge transport through the host nucleic acids largely depends on ionization potentials of the intercalators. Therefore, in this work we intend to determine vertical and adiabatic ionization potentials of the nucleic acid intercalators by using density functional theory calculations using Gaussian 16 package. We also explore the role of solvent and discuss the significance of ionization potential values in comparison with the ionization potential values of nucleic acid bases. Ionization Potential values of these intercalators range from 7.67 eV to 11.12 eV and 4.5 eV to 6.46 eV in vacuum and aqueous medium, respectively. Daunomycin is found to have lowest ionization potential value in vacuum as well as in aqueous medium. On the other hand, Proflavine (Anthraquinone) has highest ionization potential value in vacuum (aqueous medium). Non-planar intercalators exhibit distinct vertical and adiabatic ionization potential values and decrease drastically upon solvation.