title: Step-by-step rotation of a molecule-gear mounted on an atomic-scale axis.
abstract: 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.
authors.affiliation: Institute of Materials Research and Engineering, 3 Research Link, 117602, Singapore. garciac@imre.a-star.edu.sg
authors.forename: C
authors.initials: C
authors.lastname: Manzano
authors.forename: W-H
authors.initials: WH
authors.lastname: Soe
authors.forename: H S
authors.initials: HS
authors.lastname: Wong
authors.forename: F
authors.initials: F
authors.lastname: Ample
authors.forename: A
authors.initials: A
authors.lastname: Gourdon
authors.forename: N
authors.initials: N
authors.lastname: Chandrasekhar
authors.forename: C
authors.initials: C
authors.lastname: Joachim