posted on 2004-01-14, 00:00authored byMatthias Fischer, Günter Lieser, Almut Rapp, Ingo Schnell, Wael Mamdouh, Steven De Feyter, Frans C. De Schryver, Sigurd Höger
The synthesis of macrocycles with intraannular polar ester groups and extraannular oligo-alkyl
groups is described. The compounds exhibit stable liquid crystalline phases showing fan-shaped textures
under the polarizing microscope, typical for a columnar order of the molecules. X-ray powder diffraction
data of the LC phase indicate that the unit cell contains two symmetry-related units, a feature pointing
most probably to a restricted rotation of the macrocycles within a stack. The X-ray data were further
supported by solid-state NMR experiments, showing that the rigid core of the compounds does not rotate
with kHz or higher frequencies within the column in the LC phase. Apart from the organization of the
molecules in the LC phase, the 2D organization of the macrocycles at the solvent−highly oriented pyrolytic
graphite (HOPG) interface was investigated and showed that these compounds are capable of nanofunctionalizing the HOPG surface in the multinanometer regime.