CHEMISTRY YEAR
IN
REVIEW
Revisiting
Research Of 2005 C&EN steps back in time to look at three research advances and the most-cited research papers from a decade ago MOLECULAR MACHINES
COURTESY OF JAMES TOUR
‘Vehicules’ continued to inspire scientists, even if practical applications still seemed far off
LOÏC SAMUEL
Nanocar Research Kept Rolling Along
Big pickup trucks, such as those in Ford’s F-Series, were the best-selling automobiles in the U.S. in 2005. But that same year, chemists unveiled a considerably smaller vehicle—the world’s first single-molecule car. Designed and driven by the research groups of Rice University’s James M. Tour and Kevin F. Kelly, respectively, the quirky The original nanocar, shown here scooting along This year, the nanosubmarine depicted ’05 coupe featured an oligo(phenylene ethya gold surface, was reported in 2005. here sailing in solution joined the fleet. nylene) chassis and axle covalently mounted to four fullerene wheels. Because the tiny vehicle’s wheelbase was less than 5 nm, the researchers dubbed it the with a paddle-wheel-like motion. The group’s latest vehicule is a nanocar (Nano Lett. 2005, DOI: 10.1021/nl051915k). 244-atom single-molecule nanosubmarine that whizzes around in Tour tells C&EN that his original aim was fairly whimsical. He solution (Nano Lett. 2015, DOI: 10.1021/acs.nanolett.5b03764). simply wanted to make a molecule that resembled an everyday Tour’s lab isn’t the only one making nanocars. Next fall, at least object the general public would be familiar with. “This captures the five different research groups will bring their nanocars to the mind of the nonchemist,” Tour explains. “This is where we take our Center for Materials Elaboration & Structural Studies at France’s chemistry and bring it into their world.” National Center for Scientific Research (CNRS) for the world’s After that first report, scientists found nanocars have a higher first NanoCar Race. The vehicules will be propelled across a gold purpose for studying how a molecule’s atoms interact with sursurface, four at a time, by electric fields from four scanning tunnelfaces. Learning how to control that motion, Tour says, could help ing microscope tips that operate as part of a single instrument. scientists do bottom-up molecular assembly, much like enzymes “The ultimate goal is to be able to understand how a surface at do, picking up atoms and putting them into place. “I think this is the atomic level interacts with a molecule,” says Eric Masson, a the way things are going to be built in the coming years,” he adds, chemistry professor at Ohio University, who will race a supramolec“first starting with very small things, like memory on computer ular nanocar with a chassis that floats between cucurbituril wheels. chips, and then moving to larger and larger things.” “The nanocar is just a fun way to try to do this,” Masson says. In the past 10 years, Tour’s group has built a veritable fleet of “Science is a step-by-step process,” adds NanoCar Race director vehicle-type molecules, or “vehicules.” Some have six wheels, and CNRS researcher Christian Joachim. “This is a way to show some roll around on carboranes instead of fullerenes, and some inthat science and technology can be for fun and that applications clude a light-driven molecular motor to push the nanocars forward can develop years later.”—BETHANY HALFORD CEN.ACS.ORG
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DECEMBER 21, 2015
