Characterization of new rubrene analogues with heteroaryl substituents

New rubrene analogues, which are heteroaryl-tetrasubstituted tetracenes, have been developed using a simplified synthesis approach. Their stabilities in solution were improved compared to those of rubrene. The correlation among the molecular structures, crystal structures, and charge transport properties has been investigated and compared with rubrene and various rubrene analogues. Although twisted structures of a tetracene backbone have often been found in single crystal analyses, the planarity might be related to intermolecular interactions rather than the electron donating/withdrawing properties of the heteroaryl side groups. The packing motifs in thiophene-substituted derivatives did not include π-stacking of tetracene cores, which differ from the well-known structure of rubrene. However, furan-substituted derivatives can be crystallized in the π-stacking manner. These differences in the packing structure affect hole transport properties.