Autonomous use of electrical energy by an artificial molecular machine

The ability to exploit energy autonomously is one of the hallmarks of Life. Mastering such processes in artificial nanosystems can open unforeseen technological opportunities. In the last decades, light- and chemically-driven autonomous systems have been developed in relation to conformational motion and self-assembly. On the contrary, the autonomous exploitation of electrical energy remains essentially unexplored, despite being an attractive energy source. Herein we demonstrate the autonomous operation of an electrochemically-powered self-assembling nanomachine. Threading and dethreading motions of a pseudorotaxane take place autonomously in solution, between the electrodes of a scanning electrochemical microscope. This innovative actuation mode allows operating a molecular machine with an energy efficiency of 9%, unprecedented in autonomous systems. The strategy is general and can be applied to any redox-driven system, including molecular pumps that perform work repetitively. Ultimately, our study brings molecular nanoscience one step closer to everyday technology.