Single-molecule motor sits on a single-atom ball bearing

Can be run forward or in reverse, depending on where electrons are injected
December 31, 2012

The base of the device holds a ruthenium atom, and the five-armed device can rotate on top of it (credit: U. G. E. Perera et al./Nature Nanotechnology)

Researchers have created a reversible rotor that sits atop a ball bearing — a single ruthenium atom, Ars Technica reports.

The base of the system involves a boron atom that coordinates three ringed structures that are chemically similar to the bases of DNA. Nitrogens at a corner of these ringed structures coordinate the ruthenium atom, placing it at the peak of a three-sided pyramid.

The ruthenium atom acts like a ball bearing, allowing the molecule sitting atop it to rotate, spinning like a windmill tilted on to its back, with its blades oriented horizontally.

To actually get it to rotate, a scanning-tunneling microscope was used to inject electrons into the system. The added charges allowed the rings to overcome interactions with the base, and rotate. The authors could also control the direction of rotation.