Multi-Copper-Mediated DNA Base Pairs Acting as Suitable Building Blocks for the DNA-Based Nanowires

Transition-metal-mediated base pairs are under intense research because of their potential application in nanoscale molecular devices. To pursue suitable building blocks for DNA-based molecular wires, a three-copper-mediated guanine−cytosine (G3CuC) and a two-copper-mediated adenine−thymine (A2CuT) base pair were designed by equi-stoichiometric H-by-Cu replacements in this Article. Their structural and electronic properties were examined by theoretical methods. Geometrically, G3CuC and A2CuT have great resemblances to the natural GC and AT with a size-expansion of about 1.0 A due to the larger radii of Cu(I). Their significantly larger binding energies promise them to be structurally suitable for DNA helix construction. Electronically, the equi-number H-by-Cu replacement not only leads to considerable reductions of the HOMO−LUMO gaps and ionization potentials, but also enhances transverse electronic communication within isolated G3CuC and A2CuT pairs, revealed by the charge-transfer transitions in the UV ...