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Synthesis of molecular gears
Université de Toulouse, Toulouse
CEMES-CNRS
Synthetic Chemistry Inorganic Chemistry Organic Chemistry 
Full Description:

In the NanoSciences Group at CEMES, one of the current projects deals with the synthesis of molecular machines.[1] We are particularly interested in molecules allowing to study and control the
rotation movement at the nanometer scale.[2] In this context, we have synthesized a family of molecular motors, [3] whose directionality of rotation can be controlled by the tip of a Scanning Tunneling Microscope (STM).[4]

In this PhD project, we plan to synthesize a molecule geometrically analogous to a notched wheel, so as to obtain a train of molecular gears when positioning such molecules in a close manner. Up to now, all the gears studied as single molecules have been deposited directly onto the surface.[5] As a consequence, the molecules tend to diffuse, which prevents from propagating the rotation movement from one molecule to the other. In our project, the design exploits the structure of the ruthenium complex already used in the motor, with a tripodal ligand displaying thioether functions to anchor the molecule tightly on the surface. A cyclopentadienyl ligand featuring planar and sterically hindered groups, such as porphyrins, will give access to a notched wheel with one of the groups being  slightly
different in order to have a tag and to be able to follow the rotation.

This project is strongly multidisciplinary as it involves organic and coordination chemistry in combination with theoretical chemistry (a post doc will work on this task) and surface physics. This PhD thesis, even though in strong interaction with the other fields, aims at synthesizing a family of molecular gears. The envisioned synthesis involves porphyrin chemistry as well as organic and organometallic chemistry well known in the group. The initiation of the gears rotation may be achieved by the mechanical action of a STM tip as depicted on the figure (right side). These on-surface studies will be carried out in collaboration with Christian Joachim on the new 4-tip STM located in Picolab and with Prof. Saw-Wai Hla’s group at Ohio University (USA).

Profile : Master 2 student with skills in chemical synthesis and motivated to prepare a thesis. An internship in coordination chemistry or organic chemistry will be appreciated. Skills in the use of inert atmospher for synthesis (vacuum-argon line and Schlenk techniques) would be particularly appreciated. Of course, a good academic levl is required (minimum 12/20 in the french system).

Conditions : 3 years doctoral contract. Net salary of about 1400 € per month.

Application procedure : Send a CV (resume)
+ motivation letter by e-mail to Claire Kammerer kammerer@cemes.fr and Gwénaël RAPENNE rapenne@cemes.fr

[1] (a) V. Balzani, A. Credi, M. Venturi, Molecular Devices and Machines – A Journey into the Nano World, Wiley-VCH, Weinheim, 2nd ed. 2008. (b) E. R. Kay, D. A. Leigh, F. Zerbetto, Angew. Chem. Int. Ed. 2007, 46, 72.

[2] L. Grill, K. H. Rieder, F. Moresco, G. Rapenne, S.
Stojkovic, X. Bouju, C. Joachim, Nature Nanotech. 2007, 2, 95.

[3] G. Vives, H.P. Jacquot de Rouville, A. Carella, J.P. Launay, G. Rapenne, Chem. Soc. Rev. 2009, 38, 1551.

[4] U.G.E. Perera, F. Ample, J. Echeverria, H. Kersell, Y. Zhang, G. Vives, G. Rapenne, C. Joachim,
S.-W. Hla, Nature Nanotech. 2013, 8, 46.

[5] Chiaravalloti, F.; Gross, L.; Stojkovic, S. M.; Gourdon, A.; Joachim, C.; Moresco, F. Nature Mat. 2007, 6, 30.