2,6-Diarylethynylanthracenes: synthesis, morphology, and electro-optical properties

A series of 2,6-diarylethynyl-9,10-dialkoxyanthracenes have been synthesized, characterized, and evaluated for their morphological and electro-optical properties. Compounds with 2′-naphthyl and 2′-anthracyl peripheral substituents were found to have poor solubility, and were not explored in detail. However, compounds bearing 9′-anthracyl peripheral substituents exhibited better solubility, and a series of these compounds containing straight-chain and branched substituents were prepared and analyzed. These compounds were found to undergo two oxidations at +0.57 V and +0.76 V relative to a Fc/Fc+ reference. The compounds exhibited absorption with a λonset of 510 nm. Based on this, the average solution-phase HOMO–LUMO energies of these compounds were estimated to be −5.37 eV and −2.94 eV, respectively. The compounds exhibited fluorescent behavior, with an emission maximum at 505 nm. Hexoxy and Isobutoxy substituents were optimal for large crystal formation, and crystallographic studies on these two compounds show a herringbone-type arrangement with 1-dimensional pi-stacking.