Conformational Gating of Single-Molecule Conductance in Crown Ether Junctions by Li⁺ Coordination

Abstract

Herein, we report the Li+-induced modulation of single-molecule conductance in a crown ether derivative using the scanning tunnelling microscope break junction (STM-BJ) technique. Upon Li+ coordination, the conductance decreases from 10⁻³·⁷ G₀ to 10⁻⁴·² G₀. Experimental results reveal that the conductance decrease arises from a coordination-induced conformational transition, which extends the molecular junction and weakens the molecule-electrode coupling. These findings establish a clear structure-conductance correlation in crown ether systems and provide insights into the design of ion-responsive molecular electronic devices.