Introducing the World’s First Motorized Nanocar

By Jade Boyd

In follow-up work to last year’s groundbreaking invention of the world’s first single-molecule car, chemists at Rice University have produced the first motorized version of their tiny nanocar.

“We want to construct things from the bottom up, one molecule at a time, in much the same way that biological cells use enzymes to assemble proteins and other supermolecules,” says James Tour, the Chao Professor of Chemistry, professor of mechanical engineering and materials science, and professor of computer science. “Everything that’s produced through biology—from the tallest redwood to the largest whale—is built one molecule at a time. Nanocars and other synthetic transporters may prove to be a suitable alternative for bottom-up systems where biological methods aren’t practical.”

Graphic by Yasuhiro Shirai, Rice University

The nanocar consists of a rigid chassis and four alkyne axles that spin freely and swivel independently of one another. It measures just 3-by-4 nanometers and is about the same width as a strand of DNA, but much shorter. Approximately 20,000 of them could be parked side by side across the diameter of a human hair. They are the first nanoscale vehicles with an internal motor.

The motorized model of the nanocar is powered by light. Its rotating motor, a molecular framework that was developed by Ben Feringa at the University of Groningen in the Netherlands, was modified by Tour’s group so it would attach in line with the nanocar’s chassis. When light strikes the motor, it rotates in one direction, pushing the car along like a paddlewheel. The four buckyball wheels that were used in the original version of the nanocar drained energy from the motor and were replaced with spherical molecules of carbon, hydrogen, and boron called p-carborane.

Initial tests carried out in a bath of toluene solvent found that the motor rotates as designed. Follow-up tests are under way to determine whether the motorized car can be driven across a flat surface.

The research appeared in the April 13 issue of Organic Letters. Other members of the research team include postdoctoral associate Jean-François Morin and doctoral student Yasuhiro Shirai. The research was funded by the National Science Foundation, the Welch Foundation, Honda, the Natural Sciences and Engineering Research Council of Canada, and Le Fonds Québécois de la Recherche sur la Nature et les Technologies.