Effect of hydrogen migration on the electronic structure of phenol derivatives observed by single-molecule conductance

The regulation of the electronic structure of an aromatic system significantly influences its chemical reactivity, optical behavior, and electrical property. A comprehensive understanding of the impact of hydrogen atom states on the electronic structure of phenol derivatives and the ability to regulate these effects is crucial for the design and development of functional materials. Here, we employ a single-molecule junction technology to simultaneously monitor and regulate a single hydrogen atom's state in phenol derivatives. We show that the combined effects of the applied electric field and the acid-base environment in molecular solutions enable hydrogen bonding interactions to precisely control the movement of the hydrogen atom on phenol derivatives, drawing it closer to or farther away from the oxygen atom depending on the external stimuli. Complementary theoretical calculations reveal how these state changes alter electron distribution and charge transport pathways, consequently impacting molecular conductance. This study provides insights for developing controllable molecular devices.