On the interaction between gold and silver metal atoms and DNA/RNA nucleobases – a comprehensive computational study of ground state properties

The interaction between metal atoms and nucleobases has been a topic of high interest due to the wide scientific and technological implications. Combining density functional theory simulations with a literature overview, we achieved an exhaustive study of the ground state electronic properties of DNA/RNA nucleobases interacting with gold and silver atoms at three charge states: neutral, cationic, and anionic. We describe the nature of the stability and electronic properties in each hybrid metallic structure. In addition to the metal interacting with the five isolated nucleobases, we included their respective DNA-WC base pairs and one case with the protonated sugar-phosphate backbone. As a general trend, we discerned that the energetic ordering of isomers follows simple electrostatic rules as expected from previous studies. Also, we found that although the metal localizes almost all of the extra charge in the anionic system, a donation of charge is shared almost equally in the cationic system. Furthermore, the frontier orbitals of the cationic system tend to have more effects from the pairing and inclusion of the backbone than the anionic system. Finally, the electronic gap varies greatly among all of the considered structures and could be further used as a fingerprint when searching DNA-metal hybrid structures