Previous efforts have created molecular devices with coupled random motion. Śtacko et al. have realized coupling with a molecule that has unidirectional light-driven motion.
Random motion
Molecular components can couple like cogwheels, but in this case the motion is random in both directions. In a molecular brake. the rotation ratę depends on the State of a nearby molecular switch.
Directed motion
A rotary motor based on an overcrowded alkene and powered by photochemical and thermal processes is coupled with a single bond to a passive rotor consisting of a naphthalene paddle.