Self-assembly of hydrogen-bond assisted supramolecular azatriphenylene architectures

Abstract

We report on the self-assembly of a functionalized hexaazatriphenylene into supramolecular architectures where the single hexaazatriphenylene molecules are held together primarily through intermolecular hydrogen bonds between amide units. Wide and small angle X-ray scattering, polarized light microscopy, and differential scanning calorimetry revealed bulk self-organization into columnar structures. At the surfaces, scanning force microscopy experiments showed that it is possible to drive the self-organization from solutions of N-(2-ethylhexyl)-hexacarboxamidohexaazatriphenylene, towards either layers on a conductive surface like graphite or supramolecular anisotropic assemblies on an electrically insulating substrate such as muscovite mica. The growth of this latter type of architecture is primarily driven by the physical dewetting of the solution cast on the surface combined with intermolecular hydrogen bonds between the amide moieties exposed in the peripheral positions that lead to the formation of the columnar stack. Therefore, the anisotropic supramolecular azatriphenylene assemblies observed in the bulk have been also observed in thin films on a substrate poorly interacting with the adsorbate. In view of the interesting electronic properties of hexaazatriphenylene based architectures as n-type semiconductors, these results might be of interest for applications in the field of organic electronics.