Centre d’Élaboration de Matériaux et d’Etudes Structurales (UPR 8011)


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Gears

Objectives: Controlling the rotation in a molecular rack-and-pinion device

Staff: A. Gourdon, C. Joachim
Ph.D. students & Postdocs: S. M. Stojkovic (Post-doc); collaboration FU Berlin: F. Chiaravalloti, L. Gross, K.-H. Rieder, F. Moresco

The design and synthesis of molecules able to undergo a precise mechanical movement is one of the key towards future molecular mechanical nanomachines. Along these lines, we have been able to devise a gear and pinion mechanism in which a molecular 6 tooth molecules moves along a molecular gear by translation of its main axis using a STM tip. The molecule comprises six branches, and one of the branches is a pyrimidyl group whereas the other ones are phenyl groups. This gives an asymmetry in the STM images at certain resonnances and allow to attribute an orientation to the molecule (yellow arrow). The gears are step edges of a 2D crystal of this molecule.

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STM image of the molecular device. The gear is the step-edge of a monolayer of a ter-butyl substituted pyrimidopentaphenylbenzene.
© CEMES-CNRS

The experiment is done the following way: the molecule pinion is translated along the step-edge using the STM tip placed at the center of the molecule and which acts as a rotor; then the molecule rotates along this axis in a controlled way. Then, this rotation is observed by retracting the tip and acquiring an image in standard mode. The rotation direction is completely controlled by the tip translation.

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Movement of the pinion-molecule along the step-edge. The axis of the pinion (yellow arrow) is given by the contrast (white spot) due to the nitrogen tag.
© CEMES-CNRS

 

Selected publications

  • [1] "A rack and pinion device at the molecular scale" Franco Chiaravalloti, Leo Gross, Karl-Heinz Rieder, Sladjana M. Stojkovic, André Gourdon, Christian Joachim, and Francesca Moresco Nature Materials (2007) 6, 30–33.
  • [2] "Conformational dependence of tag induced intramolecular STM contrast in hexaphenylbenzene molecules" Abir De Sarkar, Carlos Manzano, We-Hyo Soe, Natarajan Chandrasekhar, A. Gourdon and Christian Joachim Surface Science Letters (2009) 603, L57-L61.
  • [3] "Step by step rotation of a molecule-gear mounted on an atomic scale axis " C. Manzano, W. -H. Soe, H. S. J. Wong, F. Ample, A. Gourdon, N. Chandrasekhar and C. Joachim Nature Materials (2009) 8(7) 576-579.

 

Fundings

Volkswagen Foundation; Europe (Nanoman, AMMIST); IMRE A*