Excited-State Dynamics in Silver-DNA Assemblies

The already rich supramolecular chemistry of DNA becomes even richer when silver(I) ions are added to nucleobase monomers or DNA strands. Silver(I) ions coordinate preferably to nitrogen atoms on the nucleobases, giving rise to supramolecular nanostructures through the formation of nucleobase coordination polymers and silver-ion-mediated base pairs (silver base pairs for short). These structures form by self-assembly in nearly activationless reactions. Silver-DNA assemblies have promising photoproperties, but realizing their potential requires understanding how their atomistic structures and the covalent and non-covalent interactions among their subunits shape their photophysics. In this chapter, we provide an overview of the diverse supramolecular structures that form when silver(I) ions are combined with DNA nucleobases and DNA strands. We then describe our initial studies of some representative silver-DNA assemblies using ultrafast spectroscopy. Improved structural understanding of silver-DNA assemblies together with the experimental and computational approaches used to study excited states in regular DNA systems during the past 25 years creates a promising research landscape for seeking first-principles understanding of photoproperty emergence in silver-DNA assemblies, which are of great interest for DNA nanotechnology.