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Addressing the properties of “Metallo-DNA” with a Ag(i)-mediated supramolecular duplex

The silver-nucleoside complex [Ag(i)-(N3-cytidine)(2)], 1, self-assembles to form a supramolecular metal-mediated base-pair array highly analogous to those seen in metallo-DNA. A combination of complementary hydrogen-bonding, hydrophobic and argentophilic interactions drive the formation of a double...

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Detalles Bibliográficos
Autores principales: Mistry, Liam, El-Zubir, Osama, Dura, Gema, Clegg, William, Waddell, Paul G., Pope, Thomas, Hofer, Werner A., Wright, Nick G., Horrocks, Benjamin R., Houlton, Andrew
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Royal Society of Chemistry 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6429620/
https://www.ncbi.nlm.nih.gov/pubmed/30996900
http://dx.doi.org/10.1039/c8sc05103h
Descripción
Sumario:The silver-nucleoside complex [Ag(i)-(N3-cytidine)(2)], 1, self-assembles to form a supramolecular metal-mediated base-pair array highly analogous to those seen in metallo-DNA. A combination of complementary hydrogen-bonding, hydrophobic and argentophilic interactions drive the formation of a double-helix with a continuous silver core. Electrical measurements on 1 show that despite having Ag···Ag distances within <5% of the metallic radii, the material is electrically insulating. This is due to the electronic structure which features a filled valence band, an empty conduction band dominated by the ligand, and a band gap of 2.5 eV. Hence, as-prepared, such Ag(i)-DNA systems should not be considered molecular nanowires but, at best, proto-wires. The structural features seen in 1 are essentially retained in the corresponding organogel which exhibits thixotropic self-healing that can be attributed to the reversible nature of the intermolecular interactions. Photo-reduced samples of the gel exhibit luminescence confirming that these poly-cytidine sequences appropriately pre-configure silver ions for the formation of quantum-confined metal clusters in line with contemporary views on DNA-templated clusters. Microscopy data reveals the resulting metal cluster/particles are approximately spherical and crystalline with lattice spacing (111) similar to bulk Ag.