Step-by-step rotation of a molecule-gear mounted on an atomic-scale axis.
Gears are microfabricated down to diameters of a few micrometres. Natural macromolecular motors, of tens of nanometres in diameter, also show gear effects. At a smaller scale, the random rotation of a single-molecule rotor encaged in a molecular stator has been observed, demonstrating that a single molecule can be rotated with the tip of a scanning tunnelling microscope (STM). A self-assembled rack-and-pinion molecular machine where the STM tip apex is the rotation axis of the pinion was also tested. Here, we present the mechanics of an intentionally constructed molecule-gear on a Au(111) surface, mounting and centring one hexa-t-butyl-pyrimidopentaphenylbenzene molecule on one atom axis. The combination of molecular design, molecular manipulation and surface atomic structure selection leads to the construction of a fundamental component of a planar single-molecule mechanical machine. The rotation of our molecule-gear is step-by-step and totally under control, demonstrating nine stable stations in both directions.
Manzano
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Institute of Materials Research and Engineering, 3 Research Link, 117602, Singapore. garciac@imre.a-star.edu.sg
Soe
W-H
WH
Wong
H S
HS
Ample
F
F
Gourdon
A
A
Chandrasekhar
N
N
Joachim
C
C