© Wiley-VCH 2007
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Stable room temperature molecular assembly of zwitterionic
organic dipoles guided by Si(111)-7x7 template effect **
Younes Makoudi, Madjid Arab, Frank Palmino, Eric Duverger, Christophe Ramseyer,
Fabien Picaud, and Frédéric Chérioux*
Synthesis of MSPS
[∗] Y. Makoudi, Dr. M. Arab, Dr. F. Palmino, Dr. E. Duverger
and Dr. F. Chérioux
Institut FEMTO-ST/LPMO UMR CNRS 6174
32, Avenue de l’Observatoire, F-25044 Besancon cedex,
Fax: (+) 33 8185 3998
Homepage ((optional)): www.femto-st.fr
Dr. F. Picaud and Prof. Dr. C. Ramseyer
Laboratoire de Physique Moléculaire, UMR CNRS 6624
16 Route de Gray, F-25030 Besancon cedex, FRANCE
[∗∗] This work was supported by the Communauté
d’Agglomération du Pays de Montbéliard. Authors thank Dr.
C. Joachim (CEMES, FRANCE) for fruitful discussions
Supporting information for this article is available on the
WWW under http://www.angewandte.org or from the
MSPS molecules have been synthesised in accordance with the method previously described by Nicoud et al.i
The procedure is based on two steps:
1) formation on the zwitterion
2) building of the large dipole
EtOH, Reflux, 10h
4-Picoline was treated at 0 °C with one equivalent of propylsultone, leading to crystalline 4-methyl-(n-
sulfonatopropyl)pyridinium, which was used for the subsequent reaction without further purification. To a
solution of 4-methyl-(n-sulfonatopropyl)pyridinium in 15 mL of anhydrous ethanol was added one equivalent of
the 4-methoxybenzaldehyde and a catalytic amount of pyrrolidine. The mixture was heated under reflux for 10 h
and then cooled to 0 °C. The precipitated product was filtered and washed with ether. The pale yellow solid was
purified by column chromatography (Silica gel, acetone, Rf close to 0.5). The pure MSPS was isolated as an
intense yellow powder after evaporation of the solvent.
1H NMR (300 MHz, CDCl3, 25°C): δ = 1.96 (quint., 3J = 7.3 Hz, 2H), 2.45 (t, 3J = 7.3 Hz,
2H), 3.76 (s, 3H), 4.62 (t, 3J = 7.3 Hz, 2H), 6.85 (d, 3J = 8.7 Hz, 2H), 7.06 (d, 3J = 16.2 Hz,
1H), 7.59 (d, 3J = 8.7 Hz, 2H), 7.69 (d, 3J = 16.2 Hz, 1H), 8.03 (d, 3J = 6.7 Hz, 2H), 8.99 (d,
3J = 6.7 Hz, 2H). MS (ESI): m/z : 333 [M+]; elemental analysis (%) calcd for C17H19NO4S
(333.10): C 61.24, H 5.74, N 4.20; found: C 61.17, H 5.81, N 4.09.
All properties of the isolated molecules are obtained by using the Vienna Ab Initio Simulation Package
(VASP),ii which is a density functional theory (DFT) code with plane wave basis set. Electron–ion interactions
were described using the projector-augmented wave (PAW) method, which was expanded within a plane wave
basis set up to a cutoff energy of 400 eV. Electron exchange and correlation effects were described by the
Perdew–Burke–Ernzerhof (PBE) GGA type exchange-correlation functional.
In order to investigate the molecule-substrate interactions, two pictures showing the DOS isolines evolution for
the entire system at different cut planes centered on the MSPS have been described in the following figures. We
have used Xcrysdeniii for the isolines dos representation.
In this top view, the methoxy group/Si(111)-7x7 interactions are proved by the DOS isolines (bias voltage +2V).
In this top view, the sulfonato/Si(111)-7x7 interactions are proved by the DOS isolines (bias voltage -2V). Download full-text
These two figures show the template effect of the surface which induces a change conformation of MSPS in
order to lead to the supramolecular self-assembly of three MSPS in a Si(111)-7x7 half-cell.
i Serbutoviez, C.; Nicoud, J.-F.; Fisher, J.; Ledoux, I. & Zyss, J. Chem. Mater. 1994, 6, 1358-1368.
ii (a) Kresse, G. & Furthmüller, J. Phys. Rev. B 1996, 54, 11169-11186. (b) Blöchl, P. E. Phys. Rev. B 1994, 50,
iii (a) Kokalj, A. J. Mol. Graphics Modelling 1999, 17, 176. (b) Kokalj, A. Comput. Mater. 2003, 28, 155.