Chemical and Electrochemical Control of Open-Shell States in Single-Molecule Electronics

Open-shell materials have attracted significant attention in the past few years due to their unique electronic structure containing unpaired electrons, which gives these compounds unusual properties. In single-molecule electronics, they have been shown to have enhanced transport efficiency and nonlinear current-voltage behaviour, both highly sought-after for future technological applications. In this contribution, we show that the behaviour of open-shell species - specifically, a diradicaloid molecular wire - is exquisitely sensitive to an electrochemical environment. Applying an electrochemical potential to the junction results in strong gating effects, up to oxidation to a poorly conductive close-shell species. Variable bias measurements, on the other hand, result in hysteretic behaviour consistent with Coulomb blockade effects and, again, oxidation to a close-shell species.