Electrochemically Gated Frustrated Lewis Pair Chemistry in Electric Double Layer

The recent discovery of frustrated Lewis pairs (FLPs) during the activation of small molecules has inspired extensive research across the full span of chemical science. Owing to the nature of weak interactions, it is experimentally challenging to directly observe and modulate FLP at the molecular scale. Here we design a boron cluster anion building block (B₁₀H₈ ^2-) and organic amine cations ([NR₄]⁺, R=-CH₃, -C₂H₅) as the FLP to prove the feasibility of controlling their interaction in the electric double layer (EDL) via an electrochemical strategy. In situ single-molecule electrical measurements and Raman monitoring of B₁₀H₈ ^2--[NR₄]⁺ FLP formed at the positively charged Au(111) electrode surface, in contrast to the free-standing B₁₀H₈ ^2- near or below the potential of zero charge (PZC). Furthermore, this FLP chemistry leads to a shift in the local density of states of boron clusters towards the E_F for enhancing electron transport, providing a new prototype of a reversible single-cluster switch that digitally switches upon controlling FLP chemistry in the electric double layer.