Hydrogen Bond-Directed Cruciform and Stacked Packing of a Pyrrole-Based Azaphenacene.

Solid state packing plays a critical role in molecular materials to be applied within the area of organic electronics since the arrangement of molecules conditions the quality of the charge transport. Due to the difficulty in accurately predicting the crystal packing simply from the molecular structure, the design of molecules which can self-organize using strategically located functional groups becomes a useful approach to induce certain order directed by noncovalent interactions. The orientation of these interactions can be intentionally controlled from the early stage of molecular design and contribute to restrict the randomness of molecular arrangement in the solid state. Herein, we describe the synthesis and solid state characterization of a novel fused polyheteroaromatic system incorporating hydrogen bond donor and acceptor sites directly into a pentacyclic structure without disrupting its conjugation. A comparative study with an analogous system without hydrogen bond acceptor sites shows the remarkable effect of the hydrogen bond-directed assembly on the crystal packing and the benefits on the π-π intermolecular overlap, crucial for charge transport processes in organic semiconductors. [ABSTRACT FROM AUTHOR]