Shape-Persistent Macrocycles with Intraannular Polar Groups:  Synthesis, Liquid Crystallinity, and 2D Organization

• Published in: Journal of the American Chemical Society 2004-01, Vol.126 (1), p.214-222
• Main Authors: Fischer, Matthias, Lieser, Günter, Rapp, Almut, Schnell, Ingo, Mamdouh, Wael, De Feyter, Steven, De Schryver, Frans C, Höger, Sigurd
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Liquid crystals; Organic polymers; Orientational order of liquid crystals; electric and magnetic field effects on order; Physicochemistry of polymers; Physics; Polymers with particular structures; Preparation, kinetics, thermodynamics, mechanism and catalysts; Structure of solids and liquids; crystallography
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja038484x

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.