Transmetalation for DNA-based Molecular Electronics

The rational design of molecular electronics remains a grand challenge of materials science. DNA nanotechnology has offered unmatched control over molecular geometry, but direct electronic functionalization has been a challenge. We present here a generalized method for tuning the local band structure of DNA using transmetalation in metal- mediated base pairs (mmDNA). We develop a method for time-resolved X-ray diffraction using self-assembling DNA crystals to establish the exchange of Ag+ and Hg2+ in T:T base pairs driven by pH exchange. Transmetalation is tracked over six reaction phases as crystal pH is changed from pH 8.0 to 11.0, and vice versa. We then perform a detailed computational analysis of the electronic configuration and transmission in the ensuing crystal structures. Our findings reveal a high conductance contrast in the lowest unoccupied molecular orbitals (LUMO) as a result of metalation. The ability to exchange single transition metal ions as a result of environmental stimuli heralds a means of modulating the conductance of DNA-based molecular electronics. In this way, we establish both a theoretical and experimental basis by which mmDNA can be leveraged to build rewritable memory devices and nanoelectronics.