title: Ag-DNA Emitter: Metal Nanorod or Supramolecular Complex?
abstract: Ligand-stabilized luminescent metal clusters, in particular, DNA-based Ag clusters, are now employed in a host of applications such as sensing and bioimaging. Despite their utility, the nature of their excited states as well as detailed structures of the luminescent metal-ligand complexes remain poorly understood. We apply a new joint experimental and theoretical approach based on QM/MM-MD simulations of the fluorescence excitation spectra for three Ag clusters synthesized on a 12-mer DNA. Contrary to a previously proposed "rod-like" model, our results show that (1) three to four Ag atoms suffice to form a partially oxidized nanocluster emitting in visible range; (2) charge transfer from Ag cluster to DNA contributes to the excited states of the complexes; and (3) excitation spectra of the clusters are strongly affected by the bonding of Ag atoms to DNA bases. The presented approach can also provide a practical way to determine the structure and properties of other luminescent metal clusters.
authors: Department of Molecular Biophysics and Polymer Physics, St. Petersburg State University , 199034 St. Petersburg, Russia.
authors: Ruslan R
authors: RR
authors: Ramazanov
authors: Department of Molecular Biophysics and Polymer Physics, St. Petersburg State University , 199034 St. Petersburg, Russia.
authors: Tomash S
authors: TS
authors: Sych
authors: Department of Molecular Biophysics and Polymer Physics, St. Petersburg State University , 199034 St. Petersburg, Russia.
authors: Zakhar V
authors: ZV
authors: Reveguk
authors: Department of Molecular Biophysics and Polymer Physics, St. Petersburg State University , 199034 St. Petersburg, Russia.
authors: Dmitriy A
authors: DA
authors: Maksimov
authors: Department of Molecular Biophysics and Polymer Physics, St. Petersburg State University , 199034 St. Petersburg, Russia.
authors: Artem A
authors: AA
authors: Vdovichev
authors: Department of Molecular Biophysics and Polymer Physics, St. Petersburg State University , 199034 St. Petersburg, Russia.
authors: Alexei I
authors: AI
authors: Kononov
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D008958:Models, Molecular; D043942:Nanotubes / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D012834:Silver; D004247:DNA