Silver Arrays Inside DNA Duplexes Constructed from Silver(I)-Mediated Pyrrolo-dC-Pyrrolo-dC Base Pairs

Tuneable silver arrays inside DNA duplexes were constructed by multiple incorporations of pyrrolo-dC-pyrrolo-dC base pairs. A short array with six silver ions was built within a DNA template. The size and positioning of the array is programmable and depends on the incorporation site of the modified base pairs. Always two silver ions were captured by one pyrrolo-dC-pyrrolo-dC pair as confirmed by melting experiments, UV and fluorescence titration experiments as well as ESI mass spectra. The silver-mediated pyrrolo-dC-pyrrolo-dC base pairs with phenyl residues in the 6-position were significantly more stable than those containing methyl substitutions. The caged silver ions are released from duplex DNA by sodium iodide but not by chloride or bromide anions, thus indicating very high stability of the metal-DNA complex.