Molecules, like Tinkertoys, link up

By developing a novel way to make molecules assemble themselves, researchers may

Scanning tunneling microscopy shows porphyrin molecules that self-assembled into wires. Nature

have opened a new route to microscopic devices, including nanoscale electronics.

Like Tinkertoys or Lincoln Logs, the molecules connect to each other only at

certain points. As a result, the molecules build into predictable shapes.

“We believe that this is a breakthrough for advancing

molecular nanotechnology,” says Takashi Yokoyama of the National Institute for

Materials Science in Nagoya, Japan. Yokoyama and his coworkers report the work in

the Oct. 11 Nature.

To make their molecular structures, the researchers tailored molecules, called

porphyrins, by adding a chemical appendage to one or more of four possible

locations. The researchers then made the molecules adsorb onto a flat, gold


The appendages, called cyanophenyl groups, made predictable linkages with each

other. When each porphyrin hosted one such appendage,

the molecules organized into trios, for example. When cyanophenyl groups were on

opposite ends of each porphyrin, the molecules lined up into wires.

The researchers now plan to measure the electronic and optical properties of the

structures, says Yokoyama. He suspects that the new technique could also work with

different molecules and on surfaces other than gold, such as silicon.

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