Molecular rotor

A University of Colorado at Boulder team has developed the first computer-generated model of a tiny, waterwheel-like molecular rotor that has been harnessed to rotate in one direction at different speeds in response to changes in the strength of an electrical field applied from the outside.

The synthetic molecule features a chemical axle with two attached "paddles" carrying opposite electrical charges, which is mounted parallel to a gold substrate surface, said Professor Josef Michl of CU-Boulder's chemistry and biochemistry department.

The researchers found that the microscopic rotor - constructed with a few hundred atoms - will turn in a desired direction at a selected frequency using an oscillating electrical field concentrated in a tiny area above the molecule.
Such molecular rotors may someday function as nanotechnology machines and be used as chemical sensors, cell-phone switches, miniature pumps or even laser-blocking goggles, he said.

In March 2004, the CU-Boulder research group led by Michl reported the synthesis of these molecules and their mounting on a gold surface - the world's first surface-mounted artificial molecular rotor, which turned spontaneously in random directions at room temperatures. While the team was able to make the rotor "flip" using electricity, the new computer model indicates such rotors can be harnessed to turn in one, desired direction at varying, prescribed speeds, he said.